Electric Charges and Fields — Physics STD 12 Science — Question

A parallel plate capacitor with air as medium between the plates has a capacitance of 10 μF. The area of capacitor is divided into two equal halves and filled with two media as shown in the figure having dielectric constant  and . The capacitance of the system will now be

(a) 10 μF

(b) 20 μF

(c) 30 μF

(d) 40 μF

A bar magnet of magnetic moment M is cut into two parts of equal length. The magnetic moment of either part is :

Of the following pairs of species which one will have the same electronic configuration for both members?

A charge Q is uniformly distributed over a large plastic plate. The electric field at a point P close to the centre of the plate is 10Vm^-1. If the plastic plate is replaced by a copper plate of the same geometrical dimensions and carrying the same charge Q, the electric field at the point P will become:

1. Zero
2. 5Vm^-1
3. 10Vm^-1
4. 20Vm^-1

Assertion  :   In Millikan's experiment for the determination of charge on an electron, oil drops of any size can be used.

Reason      : Millikan's experiment determine the charge on electron, by simply measuring the terminal velocity.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If assertion is false but reason is true.

1 Coulomb = ________ Electro Static Unit.

The difference in the lengths of a mean solar day and a sidereal day is about

(a) 1 min

(b) 4 min

(c) 15 min

(d) 56 min

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

(a) Pressure  v/s temperature of a given gas (constant volume)

(b) Kinetic energy v/s velocity of a particle

(c) Capacitance v/s charge to give a constant potential

(d) Potential v/s capacitance to give a constant charge

In Fresnel’s biprism (μ  = 1.5) experiment the distance between source and biprism is 0.3 m  and that between biprism and screen is 0.7m and angle of prism is 1°. The fringe width with light of wavelength 6000 Å will be

(a)  3 cm

(b) 0.011 cm

(c) 2 cm

(d)  4 cm

Let Q and W denote the amount of heat given to an ideal gas and the work done by it in an isothermal process.

1. Q = 0
2. W = 0
3. Q ≠ W
4. Q = W