Physics M.C.Q (1 Marks)

Assertion : A parallel plate capacitor is connected across battery through a key. A dielectric slab of constant K is introduced between the plates. The energy which is stored becomes K times.
Reason : The surface density of charge on the plate remains constant or unchanged.

Assertion : The tyres of aircraft's are slightly conducting.
Reason : If a conductor is connected to ground, the extra charge induced on conductor will flow to ground.

Assertion : Circuit containing capacitors should be handled cautiously even when there is no current.
Reason : The capacitors are very delicate and so quickly break down..

Assertion : The lightening conductor at the top of high building has sharp pointed ends.
Reason : The surface density of charge at sharp points is very high resulting in setting up of electric wind.

Assertion : The force with which one plate of a parallel plate capacitor is attracted towards the other plate is equal to square of surface density per e per unit area.
Reason : The electric field due to one charged plate of the capacitor at the location of the other is equal to surface density per e.

Assertion : At a point in space, the electric field points towards north. In the region, surrounding this point the rate of change of potential will be zero along the east and west.
Reason : Electric field due to a charge is the space around the charge

Assertion : Conductors having equal positive charge and volume, must also have same potential.
Reason : Potential depends only on charge and volume of conductor.

Assertion : The whole charge of a conductor cannot be transferred to another isolated conductor.
Reason : The total transfer of charge from one to another is not possible

Assertion : On going away from a point charge or a small electric dipole, electric field decreases at the same rate in both the cases.
Reason : Electric field is inversely proportional to square of distance from the charge or an electric dipole.

Assertion : The surface charge densities of two spherical conductors of different radii are equal. Then the electric field intensities near their surface are also equal.
Reason : Surface charge density is equal to charge per unit area.

Assertion : If a point charge q is placed in front of an infinite grounded conducting plane surface, the point charge will experience a force.
Reason : This force is due to the induced charge on the conducting surface which is at zero potential.

Assertion : Charge is quantized
Reason : Charge, which is less than 1 C is not possible

Assertion : Mass of ion is slightly differed from its element.
Reason : Ion is formed, when some electrons are removed or added so mass changes

Assertion : Charge is invariant.
Reason : Charge does not depends on speed of frame of reference.

Assertion : A charged capacitor is disconnected from a battery. Now if its plate are separated farther, the potential energy will fall.
Reason : Energy stored in a capacitor is equal to the work done in charging it.

Assertion : The capacity of a given conductor remains same even if charge is varied on it.
Reason : Capacitance depends upon nearly medium as well as size and shape of conductor.

Assertion : Annihilation of electron and positron is an example of decay of charges.
Reason : In the process of annihilation an electron and a positron combine to give a gamma particle.

Assertion : When charges are shared between any two bodies, no charge is really lost, but some loss of energy does occur.
Reason : Some energy disappears in the form of heat, sparking etc.

Assertion : Dielectric breakdown occurs under the influence of an intense light beam.
Reason : Electromagnetic radiations exert pressure.

Assertion : If a proton and an electron are placed in the same uniform electric field. They experience different acceleration.
Reason : Electric force on a test charge is independent of its mass.

Assertion : Electric lines of force cross each other.
Reason : Electric field at a point superimpose to give one resultant electric field.

Four metallic plates each with a surface area of one side A are placed at a distance d from each other. The plates are connected as shown in the circuit diagram. Then the capacitance of the system between a and b is

Assertion : A metallic shield in form of a hollow shell may be built to block an electric field.
Reason : In a hollow spherical shield, the electric field inside it is zero at every point.

Assertion : Electrons move away from a low potential to high potential region.
Reason : Because electrons has negative charge

Assertion : If the distance between parallel plates of a capacitor is halved and dielectric constant is made three times, then the capacitor becomes 6 times.
Reason : Capacity of the capacitor does not depend upon the nature of the material.

The variation of potential with distance R from a fixed point is as shown below. The electric field at R = 5 m is








 

The figure gives the electric potential V as a function of distance through five regions on x-axis. Which of the following is true for the electric field E in these regions

Which of the following graphs shows the variation of electric field E due to a hollow spherical conductor of radius R as a function of distance from the centre of the sphere

The electric field due to a uniformly charged sphere of radius R as a function of the distance from its centre is represented graphically by

What physical quantities may X and Y represent ? (Y represents the first mentioned quantity)







 

Between the plates of a parallel plate capacitor a dielectric plate is introduced just to fill the space between the plates. The capacitor is charged and later disconnected from the battery. The dielectric plate is slowly drawn out of the capacitor parallel to the plates. The plot of the potential difference across the plates and the length of the dielectric plate drawn out is

A fully charged capacitor has a capacitance ‘C’. It is discharged through a small coil of resistance wire embedded in a thermally insulated block of specific heat capacity ‘s’ and mass ‘m’. If the temperature of the block is raised by ‘ ∆T ’, the potential difference ‘V’ across the capacitance is

The plates of a parallel plate condenser are pulled apart with a velocity v. If at any instant their mutual distance of separation is d, then the magnitude of the time of rate of change of capacity depends on d as follows

The plates of a capacitor are charged to a potential difference of 320 volts and are then connected across a resistor. The potential difference across the capacitor decays exponentially with time. After 1 second the potential difference between the plates of the capacitor is 240 volts, then after 2 and 3 seconds the potential difference between the plates will be

In the given figure each plate of capacitance C has partial value of charge

Consider the situation shown in the figure. The capacitor A has a charge q on it whereas B is uncharged. The charge appearing on the capacitor B a long time after the switch is closed is

For the circuit shown, which of the following statements is true

In the given circuit if point C is connected to the earth and a potential of +2000 V is given to the point A, the potential at B is

Condenser A has a capacity of 15μF when it is filled with a medium of dielectric constant 15. Another condenser B has a capacity of 1 μF with air between the plates. Both are charged separately by a battery of 100 V. After charging, both are connected in parallel without the battery and the dielectric medium being removed. The common potential now is

A parallel plate capacitor of capacitance C is connected to a battery and is charged to a potential difference V. Another capacitor of capacitance 2C is connected to another battery and is charged to potential difference 2V. The charging batteries are now disconnected and the capacitors are connected in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal of the other. The final energy of the configuration is 

Figure given below shows two identical parallel plate capacitors connected to a battery with switch S closed. The switch is now opened and the free space between the plate of capacitors is filled with a dielectric of dielectric constant 3. What will be the ratio of total electrostatic energy stored in both capacitors before and after the introduction of the dielectric

In an RC circuit while charging, the graph of in i versus time is as shown by the dotted line in the diagram figure, where i is the current. When the value of the resistance is doubled, which of the solid curve best represents the variation of in i versus time

Two identical point charges are placed at a separation of d. P is a point on the line joining the charges, at a distance x from any one charge. The field at P is E, E is plotted against x for values of x from close to zero to slightly less than d. Which of the following represents the resulting curve

Two condensers of capacities 2C and C are joined in parallel and charged upto potential V. The battery is removed and the condenser of capacity C is filled completely with a medium of dielectric constant K. The p.d. across the capacitors will now be

Equipotential surfaces are shown in figure. Then the electric field strength will be

Change Q on a capacitor varies with voltage V as shown in the figure, where Q is taken along the X-axis and V along the Y-axis. The area of triangle OAB represents

An infinite number of identical capacitors each of capacitance 1 μF are connected as in adjoining figure. Then the equivalent capacitance between A and B is

To form a composite 16Μf, 1000 V capacitor from a supply of identical capacitors marked 8 μF, 250 V we require a minimum number of capacitors

Five identical plates each of area A are joined as shown in the figure. The distance between the plates is d. The plates are connected to a potential difference of V volts. The charge on plates 1 and 4 will be

Capacitance of a capacitor made by a thin metal foil is 2μF. If the foil is folded with paper of thickness 0.15 mm, dielectric constant of paper is 2.5 and width of paper is 400 mm , then length of foil will be

A dielectric slab of thickness d is inserted in a parallel plate capacitor whose negative plate is at x = 0 and positive plate is at x = 3d. The slab is equidistant from the plates. The capacitor is given some charge. As one goes from 0 to 3d

A parallel plate air capacitor has a capacitance of 100 μμF. The plates are at a distance d apart. If a slab of thickness t( t ≤ d) and dielectric constant 5 is introduced between the parallel plates, then the capacitance will be

Four charges equal to – Q are placed at the four corners of a square and a charge q is at its centre. If the system is in equilibrium the value of q is

Six charges, three positive and three negative of equal magnitude are to be placed at the vertices of a regular hexagon such that the electric field at O is double the electric field when only one positive charge of same magnitude is placed at R. Which of the following arrangements of charges is possible for P, Q, R, S, T and U respectively

Two point charges (+Q) and (-2Q) are fixed on the X-axis at positions a and 2a from origin respectively. At what positions on the axis, the resultant electric field is zero

A point charge of 40 stat coulomb is placed 2 cm in front of an earthed metallic plane plate of large size. Then the force of attraction on the point charge is

A solid conducting sphere having a charge Q is surrounded by an uncharged concentric conducting hollow spherical shell. Let the potential difference between the surface of the solid sphere and that of the outer surface of the hollow shell be V. If the shell is now given a charge of –3Q, the new potential difference between the same two surfaces is

An elementary particle of mass m and charge +e is projected with velocity v at a much more massive particle of charge Ze, where Z > 0. What is the closest possible approach of the incident particle 

A finite ladder is constructed by connecting several sections of 2μF,4 μF capacitor combinations as shown in the figure. It is terminated by a capacitor of capacitance C. What value should be chosen for C such that the equivalent capacitance of the ladder between the points A and B becomes independent of the number of sections in between

Two equal point charges are fixed at x = -a and x = +a on the x-axis. Another point charge Q is placed at the origin. The Change in the electrical potential energy of Q, when it is displaced by a small distance x along the x-axis, is approximately proportional to(a) (b) (c) (d)

The electric potential at a point (x, y) in the x - y plane is given by V = -kxy. The field intensity at a distance r from the origin varies as

In the figure a potential of + 1200 V is given to point A and point B is earthed, what is the potential at the point P

A uniform electric field pointing in positive x-direction exists in a region. Let A be the origin, B be the point on the x-axis at x = +1 cm and C be the point on the y-axis at y = +1 cm. Then the potentials at the points A, B and C satisfy 

Consider two points 1 and 2 in a region outside a charged sphere. Two points are not very far away from the sphere. If E and V represent the electric field vector and the electric potential, which of the following is not possible

Charge q is uniformly distributed over a thin half ring of radius R. The electric field at the centre of the ring is

The charge on 500 cc of water due to protons will be

A non-conducting solid sphere of radius R is uniformly charged. The magnitude of the electric field due to the sphere at a distance r from its centre

A charged particle q is shot towards another charged particle Q which is fixed, with a speed v. It approaches Q upto a closest distance r and then returns. If q were given a speed 2v, the closest distances of approach would be

A solid metallic sphere has a charge +3Q. Concentric with this sphere is a conducting spherical shell having charge -Q. The radius of the sphere is a and that of the spherical shell is b(b > a). What is the electric field at a distance R(a < R < b) from the centre 

Two equal charges q of opposite sign separated by a distance 2a constitute an electric dipole of dipole moment p. If P is a point at a distance r from the centre of the dipole and the line joining the centre of the dipole to this point makes an angle θ with the axis of the dipole, then the potential at P is given by (r >> 2a) (Where p = 2qa)

A point charge q is placed at a distance a/2 directly above the centre of a square of side a. The electric flux through the square is

An ellipsoidal cavity is carved within a perfect conductor. A positive charge q is placed at the centre of the cavity. The points A and B are on the cavity surface as shown in the figure. Then

A metallic shell has a point charge ‘q’ kept inside its cavity. Which one of the following diagrams correctly represents the electric lines of forces

Three capacitors of capacitance 1 mF, 2 mF and 3 mF are connected in series and a potential difference of 11 V is applied across the combination. Then, the potential difference across the plates of 1 mF capacitor is

Effective capacitance between A and B in the figure shown is (all capacitance are in mF)

Three capacitors 2, 3 and 6 mF are joined in series with each other. What is the minimum effective capacitance

Three plates of common surface area A are connected as shown. The effective capacitance will be

All six capacitors shown are identical, Each can withstand maximum 200 volts between its terminals. The maximum voltage that can be safely applied between A and B is

In the figure, three capacitors each of capacitance 6 pF are connected in series. The total capacitance of the combination will be

Three positive charges of equal value q are placed at the vertices of an equilateral triangle. The resulting lines of force should be sketched as in

Two capacitors A and B are connected in series with a battery as shown in the figure. When the switch S is closed and the two capacitors get charged fully, then








 

Two capacitors of capacitance 2 μF and 3μF are joined in series. Outer plate first capacitor is at 1000 volt and outer plate of second capacitor is earthed (grounded). Now the potential on inner plate of each capacitor will be

A series combination of three capacitors of capacities 1μF, 2 μF and 8 μF is connected to a battery of e.m.f. 13 volt. The potential difference across the plates of 2 μF capacitor will be

Three capacitors each of capacity 4μF are to be connected in such a way that the effective capacitance is 6 μF. This can be done by

In the figure shown, the effective capacitance between the points A and B, if each has capacitance C, is

Four equal capacitors, each of capacity C, are arranged as shown. The effective capacitance between A and B is

In the circuit as shown in the figure the effective capacitance between A and B is

The charge on any one of the 2 μF capacitors and 1 μF capacitor will be given respectively (in μC ) as

Two capacitors of 1mF and 2mF are connected in series, the resultant capacitance will be

A capacitor of 10mF charged up to 250 volts is connected in parallel with another capacitor of 5mF charged up to 100 volts. The common potential is

Two capacitors of capacitances 3 μF and 6 μF are charged to a potential of 12 V each. They are now connected to each other, with the positive plate of each joined to the negative plate of the other. The potential difference across each will be

Three capacitors of 2μF, 3μF and 6μF are joined in series and the combination is charged by means of a 24 volt battery. The potential difference between the plates of the 6 μF capacitor is

The equivalent capacitance in the circuit between A and B will be
(a) (b) (c) (d)

A 20F capacitor is charged to 5V and isolated. It is then connected in parallel with an uncharged 30F capacitor. The decrease in the energy of the system will be

Consider a parallel plate capacitor of 10 μF (micro-farad) with air filled in the gap between the plates. Now one half of the space between the plates is filled with a dielectric of dielectric constant 4, as shown in the figure. The capacity of the capacitor changes to

Three capacitors of capacitance 3 μF , 10 μF and 15 μF are connected in series to a voltage source of 100V. The charge on 15 μF is

In the figure a capacitor is filled with dielectrics. The resultant capacitance is

Two capacitors of 10 μF and 20 μF are connected in series with a 30V battery. The charge on the capacitors will be, respectively

Equivalent capacitance between A and B is

The effective capacitance between the points P and Q of the arrangement shown in the figure is

In the circuit here, the steady state voltage across capacitor C is a fraction of the battery e.m.f. The fraction is decided by

Ten capacitor are joined in parallel and charged with a battery up to a potential V. They are then disconnected from battery and joined again in series then the potential of this combination will be

A potential difference of 300 volts is applied to a combination of 2.0mF and 8.0mF capacitors connected in series. The charge on the 2.0mF capacitor is

What is the effective capacitance between A and B in the following figure

When two identical capacitors are in series have 3mF capacitance and when parallel 12mF. What is the capacitance of each

In the circuit shown in figure, each capacitor has a capacity of 3μF. The equivalent capacity between A and B is

The capacitance between the points A and B in the given circuit will be

The equivalent capacitance between A and B is

A capacitor of 20 μF is charged to 500 volts and connected in parallel with another capacitor of 10 μF and charged to 200 volts. The common potential is

The resultant capacitance of given circuit is

The charge on a capacitor of capacitance 10 μF connected as shown in the figure is

The combined capacity of the parallel combination of two capacitors is four times their combined capacity when connected in series. This means that

What is the effective capacitance between points X and Y

A 10 μF capacitor is charged to a potential difference of 50 V and is connected to another uncharged capacitor in parallel. Now the common potential difference becomes 20 volt. The capacitance of second capacitor is

Choose the incorrect statement from the following: When two identical capacitors are charged individually to different potentials and connected parallel to each other after disconnecting them from the source

Three identical capacitors are combined differently. For the same voltage to each combination, the one that stores the greatest energy is

In the adjoining figure, four capacitors are shown with their respective capacities and the P.D. applied. The charge and the P.D. across the 4μF capacitor will be

Four capacitors are connected as shown in the figure. Their capacities are indicated in the figure. The effective capacitance between points x and y is (in μF)

Three capacitors of 2.0, 3.0 and 6.0 μF are connected in series to a 10 V source. The charge on the 3.0 μF capacitor is

Four capacitors are connected in a circuit as shown in the figure. The effective capacitance in μF between points A and B will be

Three capacitors each of 6μF are available. The minimum and maximum capacitances which may be obtained are

The total capacity of the system of capacitors shown in the adjoining figure between the points A and B is

Four capacitors are connected as shown in the equivalent capacitance between the points P and Q is

Two identical parallel plate capacitors are connected in series to a battery of 100 V. A dielectric slab of dielectric constant 4.0 is inserted between the plates of second capacitor. The potential difference across the capacitors will now be respectively

Two capacitors of 3pF and 6pF are connected in series and a potential difference of 5000 V is applied across the combination. They are then disconnected and reconnected in parallel. The potential between the plates is

A condenser of capacitance 10 μF has been charged to 100 volts. It is now connected to another uncharged condenser in parallel. The common potential becomes 40 volts. The capacitance of another condenser is

In the circuit shown in the figure, the potential difference across the 4.5mF capacitor is

0.2 Fcapacitor is charged to 600 V by a battery. On removing the battery, it is connected with another parallel plate condenser of 1F. The potential decreases to

A condenser having a capacity of 6mF is charged to 100 V and is then joined to an uncharged condenser of 14 μF and then removed. The ratio of the charges on 6mF and 14mF and the potential of 6mF will be

What is the equivalent capacitance between A and B in the given figure (all are in farad)

In the following circuit, the resultant capacitance between A and B is 1mF. Then value of C is
(a) (b) (c) (d)

The resultant capacitance between A and B in the following figure is equal to

In the connections shown in the adjoining figure, the equivalent capacity between A and B will be

A capacitor having capacitance C is charged to a voltage V. It is then removed and connected in parallel with another identical capacitor which is uncharged. The new charge on each capacitor is now

A 4 μF condenser is connected in parallel to another condenser of 8 μF. Both the condensers are then connected in series with a 12 μF condenser and charged to 20 volts. The charge on the plate of 4 μF condenser is

Two capacitors each of capacity 2 μF are connected in parallel. This system is connected in series with a third capacitor of 12 μF capacity. The equivalent capacity of the system will be

A parallel plate capacitor is made by stacking n equally spaced plates connected alternately. If the capacitance between any two plates is C then the resultant capacitance is

Four plates of the same area of cross-section are joined as shown in the figure. The distance between each plate is d. The equivalent capacity across A and B will be

The capacities and connection of five capacitors are shown in the adjoining figure. The potential difference between the points A and B is 60 volts . Then the equivalent capacity between A and B and the charge on 5μF capacitance will be respectively

Two condensers of capacities 1μF and 2 μF are connected in series and the system is charged to 120 volts. Then the P.D. on 1 μF capacitor (in volts) will be

The equivalent capacitance between A and B in the figure is 1 μF. Then the value of capacitance C is






 

Four capacitors of each of capacity 3μF are connected as shown in the adjoining figure. The ratio of equivalent capacitance between A and B and between A and C will be







 

Two capacitors of equal capacity are first connected in parallel and then in series. The ratio of the total capacities in the two cases will be

Three capacitances of capacity 10 μF, 5 μF and 5 μF are connected in parallel. The total capacity will be

The capacitor of capacitance 4 μF and 6 μF are connected in series. A potential difference of 500 volts is applied to the outer plates of the two capacitor system. The potential difference across the plates of capacitor of 4 μF capacitance is

Two condensers of capacity 0.3 μF and 0.6 μF respectively are connected in series. The combination is connected across a potential of 6 volts . The ratio of energies stored by the condensers will be 

In the circuit diagram shown in the adjoining figure, the resultant capacitance between P and Q is

2μF capacitance has potential difference across its two terminals 200 volts. It is disconnected with battery and then another uncharged capacitance is connected in parallel to it, then P.D. becomes 20 volts. Then the capacity of another capacitance will be

Two capacitors each of 1μF capacitance are connected in parallel and are then charged by 200 volts d.c. supply. The total energy of their charges (in joules) is

A capacitor is charged to 200 volt it has 0.1 coulomb charge. When it is discharged, energy will be

Four condensers are joined as shown in the adjoining figure. The capacity of each is 8 μF. The equivalent capacity between the points A and B will be

The capacitor of capacitance 4μF and 6 μF are connected in series. A potential difference of 500 volts applied to the outer plates of the two capacitor system. Then the charge on each capacitor is numerically

n identical condensers are joined in parallel and are charged to potential V. Now they are separated and joined in series. Then the total energy and potential difference of the combination will be

Three capacitors each of capacitance 1μF are connected in parallel. To this combination, a fourth capacitor of capacitance 1μF is connected in series. The resultant capacitance of the system is

Five capacitors of 10 μF capacity each are connected to a d.c. potential of 100 volts as shown in the adjoining figure. The equivalent capacitance between the points A and B will be equal to

The potentials of the two plates of capacitor are +10V and –10 V. The charge on one of the plates is 40 C. The capacitance of the capacitor is

If the distance between the plates of parallel plate capacitor is halved and the dielectric constant of dielectric is doubled, then its capacity will

The capacity of an air condenser is 2.0 mF. If a medium is placed between its plates. The capacity becomes 12 mF. The dielectric constant of the medium will be

A 4 mF condenser is charged to 400 V and then its plates are joined through a resistance. The heat produced in the resistance is

When a lamp is connected in series with capacitor, then

When a dielectric material is introduced between the plates of a charges condenser, then electric field between the plates

On increasing the plate separation of a charged condenser, the energy

An air filled parallel plate capacitor has capacity C. If distance between plates is doubled and it is immersed in a liquid then apacity becomes twice. Dielectric constant of the liquid is

A spherical drop of capacitance 1 mF is broken into eight drops of equal radius. Then, the capacitance of each small drop is ......

A 40 mF capacitor in a defibrillator is charged to 3000 V. The energy stored in the capacitor is sent through the patient during a pulse of duration 2ms. The power delivered to the patient is

If a dielectric substance is introduced between the plates of a charged air-gap capacitor. The energy of the capacitor will

If eight identical drops are joined to form a bigger drop, the potential on bigger as compared to that on smaller drop will be

A charge of 40 μC is given to a capacitor having capacitance C = 10 μF. The stored energy in ergs is

As in figure shown, if a capacitor C is charged by connecting it with resistance R, then energy is given by the battery will be

A parallel plate capacitor carries a charge q. The distance between the plates is doubled by application of a force. The work done by the force is

64 drops of mercury each charged to a potential of 10V. They are combined to form one bigger drop. The potential of this drop will be (Assume all the drops to be spherical)