Nuclei — Physics STD 12 Science — Question

The relaxation time in conductors:

The lowest resistance which can be obtained by connecting 10 resistors each of 1/10 ohm is

(a) 1/250 Ω

(b) 1/200 Ω

(c) 1/100 Ω

(d) 1/10 Ω

A straight copper wire is moved in a uniform magnetic field such that it cuts the magnetic lines of force. Then

The factor by which the capacitance increases from its vacuum value when the dielectric is inserted fully between the plates of a capacitor, is called as:

If aperture of lens is halved then image will be

(a) No effect on size	(b) Intensity of image decreases
(c) Both (a) and (b)	(d) None of these

 The resistivity of certain metals or alloys drops to zero when they are cooled below a certain temperature, this phenomenon is known as __________.

Atomic power station at Tarapore has a generating capacity of 200 MW. The energy generated in a day by this station is

(a) 200 MW

(b) 200 J

(c) 4800  J

(d) 1728  J

When moving electron comes closer to other stationary electron, then its kinetic energy and potential energy respectively _____ and _____.

Fusion reaction is initiated with the help of

(a) Low temperature

(b) High temperature

(c) Neutrons

(d) Any particle

A long magnetic needle of length 2L, magnetic moment M and pole strength m units is broken into two pieces at the middle. The magnetic moment and pole strength of each piece will be

(a)

(b) M,

(c)

(d) M, m