Physics M.C.Q (1 Marks)

The n rows each containing m cells in series are joined in parallel. Maximum current is taken from this combination across an external resistance of 3W resistance. If the total number of cells used are 24 and internal resistance of each cell is 0.5 W then

An unknown resistance R₁ is connected in series with a resistance of 10 W. This combinations is connected to one gap of a metre bridge while a resistance R₂ is connected in the other gap. The balance point is at 50 cm. Now, when the 10 W resistance is removed the balance point shifts to 40 cm. The value of R₁ is (in ohm)

In the figure given below, the current passing through 6 Ω  resistor is

A 3volt battery with negligible internal resistance is connected in a circuit as shown in the figure.  The current I, in the circuit will be

The equivalent resistance of the following infinite network of resistances is

What is the equivalent resistance of the circuit

The equivalent resistance between x and y in the circuit shown is

What is the equivalent resistance between A and B

A student has 10 resistors of resistance ‘r’. The minimum resistance made by him from given resistors is

Masses of 3 wires of same metal are in the ratio 1 : 2 : 3 and their lengths are in the ratio 3 : 2 : 1.  The electrical resistances are in ratio

Which of the following is vector quantity

The electric resistance of a certain wire of iron is R. If its length and radius are both doubled, then

In the figure a carbon resistor has bands of different colours on its body as mentioned in the figure.  The value of the resistance is

In the given circuit the current I₁ is

The potential difference between points  A and  B of adjoining figure is

(a)

(b)

(c)

(d) 2 V

The current in the arm CD of the circuit will be

(a)

(b)

(c)

(d)

The reading of the ideal voltmeter in the adjoining diagram will be

For what value of R the net resistance of the circuit will be 18 ohms

The magnitude and direction of the current in the circuit shown will be

Which arrangement of four identical resistances should be used to draw maximum energy from a cell of voltage V

Three equal resistances each of value R are joined as shown in the figure. The equivalent resistance between M and N is

The current in the following circuit is

Which of the adjoining graphs represents ohmic resistance

(a)

(b)

(c)

(d)

Eels are able to generate current with biological cells called electroplaques. The electroplaques in an eel are arranged in 100 rows, each row stretching horizontally along the body of the fish containing 5000 electroplaques. The arrangement is suggestively shown below. Each electroplaques has an emf of 0.15 V and internal resistance of 0.25 W

The water surrounding the eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of 500 W, the current an eel can produce in water is about

Equal potentials are applied on an iron and copper wire of same length.  In order to have the same current flow in the two wires, the ratio r (iron)/r (copper) of their radii must be (Given that specific resistance of iron =  ohm–m and specific resistance of copper =  1.7  ohm-m)

In the circuit shown below,  The reading of the voltmeter V is

If you are provided three resistances 2 W, 3 W and 6 W. How will you connect them so as to obtain the equivalent resistance of 4 W

The resistance of a conductor increases with

A uniform wire of resistance R is uniformly compressed along its length, until its radius becomes n times the original radius.  Now resistance of the wire becomes

The resistance of an incandescent lamp is

In the circuit shown here, what is the value of the unknown resistor R so that the total resistance of the circuit between points P and Q is also equal to R

The resistance of a 5 cm long wire is 10 W.  It is uniformly stretched so that its length becomes 20 cm.  The resistance of the wire is

At room temperature, copper has free electron density of 8.4   per .  The copper conductor has a cross-section of 10^–6 m² and carries a current of 5.4 A.  The electron drift velocity in copper is

There is a current of 40 ampere in a wire of   area of cross-section.  If the number of free electron per   is ,  then the drift velocity will be     

The drift velocity does not depend upon

If a wire of resistance R is melted and recasted to half of its length, then the new resistance of the wire will be

Calculate the amount of charge flowing in 2 minutes in a wire of resistance 10 W when a potential difference of 20 V is applied between its ends

If an observer is moving with respect to a stationary electron, then he observes

In the circuit shown below the resistance of the galvanometer is 20 W.  In which case of the following alternatives are the currents arranged strictly in the decreasing order

The figure below shows currents in a part of electric circuit. The current i is

A nichrome wire 50 cm long and one square millimetre cross-section carries a current of 4A when connected to a 2V battery.  The resistivity of nichrome wire in ohm metre is

If potential  V = 100 ± 0.5 Volt and current I = 10  ± 0.2 amp are given to us.  Then what will be the value of resistance

Five equal resistances each of resistance R are connected as shown in the figure. A battery of V volts is connected between A and B. The current flowing in AFCEB will be

The charge of an electron is 1.6 × 10^–19 C.  How many electrons strike the screen of a cathode ray tube each second when the beam current is 16 mA

An electron revolves 6 × 10¹⁵ times/sec in circular loop.  The current in the loop is

At what temperature will the resistance of a copper wire become three times its value at 0 ^oC  (Temperature coefficient of resistance for copper = 4 × 10^–3 per ^oC )

A rod of a certain metal is 1.0 m long and 0.6 cm in diameter.  Its resistance is 3.0 ×   ohm.  Another disc made of the same metal is 2.0 cm in diameter and 1.0 mm thick.  What is the resistance between the round faces of the disc

If an electron revolves in the path of a circle of radius of 0.5  m at frequency of 5 × 10¹⁵ cycles/s the electric current in the circle is (Charge of an electron = 1.6 × 10^–19 C )

The resistance of a conductor is 5 ohm at 50 ^oC and 6 ohm at 100 ^oC.  Its resistance at  0 ^oC is

The current in the adjoining circuit will be