Electric Charges and Fields — Physics STD 12 Science — Question

In the circuit shown below, the power developed in the 6W resistor is 6 watt. The power in watts developed in the 4W resistor is

(a) 16

(b) 9

(c) 6

(d) 4

An element has number of electrons  = 2. Then what will be its atomic number?.

A galvanometer of resistance 20 W is to be converted into an ammeter of range 1 A.  If a current of 1 mA produces full scale deflection, the shunt required for the purpose is

(a) 0.01 W

(b) 0.05 W

(c) 0.02 W

(d) 0.04 W

If for a thermocouple  is the neutral temperature,  is the temperature of the cold junction and  is the temperature of inversion, then

(a)

(b)

(c)

(d) None of these

The energy equivalent of 1 kilogram of matter is about

(a)  J

(b) 1 J

(c)  J

(d)  J

The energy required to excite an electron from the ground state of hydrogen atom to the first excited state, is

(a) 1.602

(b) 1.619

(c) 1.632

(d) 1.656

 A variable condenser is permanently connected to a 100 V battery. If the capacity is changed from 2μF to 10 μF, then change in energy is equal to

(a) 2

(b) 2.5

(c) 3.5

(d) 4

A liquid can easily change its shape but a solid can not because.

1. The density of a liquid is smaller than that of a solid.
2. The forces between the molecules is stronger in solid than in liquids.
3. The atoms combine to form bigger molecules in a solid.
4. The average separation between the molecules is larger in solids.

A steady electric current is flowing through a cylindrical conductor.

Huygen's conception of secondary waves

(a) Allow us to find the focal length of a thick lens

(b) Is a geometrical method to find a wavefront

(c) Is used to determine the velocity of light

(d) Is used to explain polarisation