Nuclei — Physics STD 12 Science — Question

A capacitor is connected to a cell of emf E having some internal resistance r. The potential difference across the

(a) Cell is < E

(b) Cell is E

(c) Capacitor is > E

(d) Capacitor is < E

In the graph given below. If the slope is 4.12  V-sec, then value of ‘h’ should be

(a) 6.6  J-sec

(b) 6.6  J-sec

(c) 9.1  J-sec

(d) None of these

The fusion of light elements take place at about the temperatures of about:

The magnetic flux linked with a coil at any instant ‘t’ is given by f = 5t³ – 100t + 300, the e.m.f. induced in the coil at t = 2 second is

(a) – 40 V

(b) 40 V

(c) 140 V

(d) 300 V

Two bodies A and B having equal surface areas are maintained at temperatures 10^°C and 20^°C. The thermal radiation emitted in a given time by A and B are in the ratio:

1. 1 : 1.15
2. 1 : 2
3. 1 : 4
4. 1 : 16

Smaller pieces of heavy stones and metals which on entering earth's atmosphere burns out are

(a) Comets

(b) Meteorites

(c) Asteroids

(d) All of these

Time period of a freely suspended magnet does not depend upon

(a) Length of the magnet

(b) Pole strength of the magnet

(c) Horizontal component of earth's magnetic field

(d) Length of the suspension thread

To get line spectrum, the substances are excited in their:

The upper limit temperature of a super conductor is: