Electric Charges and Fields — Physics STD 12 Science — Question

A wave going in a solid.

1. Must be longitudinal
2. May be longitudinal
3. Must be transverse
4. May be transverse.

Young's experiment establishes that

(a) Light consists of waves

(b) Light consists of particles

(c) Light consists of neither particles nor waves

(d) Light consists of both particles and waves

The wavefronts of a light wave travelling in vacuum are given by x + y + z = c. The angle made by the direction of propagation of light with the X-axis is:

The truth table shown in figure is for

(a) XOR

(b) AND

(c) XNOR

(d) OR

The size of the nucleus is approximately :

Binary of decimal number 25 is :

If ionisation energy of hydrogen atom in ground state is 13.6 eV , then ionisation energy of first excited state will be :

The capacitor of an oscillatory circuit of negligible resistance is enclosed in a evacuated container. The frequency of the circuit is 150 kHZ and when the container is filled with a gas, the frequency changes by 100 HZ. The dielectric constant of the gas.

The distance between the plates of a parallel plate condenser is 4mm and potential difference is 60 volts. If the distance between the plates is increased to 12mm, then

(a) The potential difference of the condenser will become 180 volts

(b) The P.D. will become 20 volts

(c) The P.D. will remain unchanged

(d) The charge on condenser will reduce to one third

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

(a) 400 m/s

(b) 0.4 m/s

(c) 0.4 mm/s

(d) 72 m/s