Nuclei — Physics STD 12 Science — Question

The resistance of a coil is 4.2 Ω at 100 ^oC and the temperature coefficient of resistance of its material is 0.004/^o C.  Its resistance at 0^o C is

(a) 6.5 Ω

(b) 5 Ω

(c) 3 Ω

(d) 4 Ω

An oil drop having charge 2e is kept stationary between two parallel horizontal plates 2.0 cm apart when a potential difference of 12000 volts is applied between them. If the density of oil is 900 kg/m³, the radius of the drop will be

(a) 2.0

(b) 1.7

(c) 1.4

(d) 1.1

When a glass rod is rubbed with silk, it

(a) Gains electrons from silk	(b) Gives electrons to silk
(c) Gains protons from silk	(d) Gives protons to silk

The source of stellar energy is:

From the following, what charges can be present on oil drops in Millikan's experiment (Here e is the electronic charge)

(a) Zero, equal to the magnitude of charge on α - particle

(b) 2e, 1.6

(c) 1.6

(d) 1.5 e, e

‘X’ is a substance which does not allow the flow of charges through it but permits them to exert electrostatic forces on one another through it. Identify X.

Light from the constellation Virgo is observed to increase in wavelength by 0.4%. With respect to Earth the constellation is

(a) Moving away with velocity 1.2 × 106 m/s

(b) Coming closer with velocity 1.2 × 106 m/s

(c) Moving away with velocity 4 × 106 m/s

(d) Coming closer with velocity 4 × 106 m/s

When we rub our comb with hair and then take near to the paper pieces, all pieces get stuck to the comb. This happens due tyo which phenomena?

The binding energies per nucleon for a deuteron and an α- particle are x₁ and x₂ respectively. What will be the energy Q released in the reaction  

(a) 4

(b) 4

(c) 2(

(d) 2

A block of mass m slides down a smooth vertical circular track. During the motion, the block is in:

1. Vertical equilibrium.
2. Horizontal equilibrium.
3. Radial equilibrium.
4. None of these.