Atoms — Physics STD 12 Science — Question

Figure shows the position of a particle moving on the X-axis as a function of time.

1. The particle has come to rest 6 times.
2. The maximum speed is at t = 6s.
3. The velocity remains positive for t = 0 to t = 6s.
4. The average velocity for the total period shown is negative.

A point charge q is rotated along a circle in the electric field generated by another point charge Q. The work done by the electric field on the rotating charge in one complete revolution is_______?

For the stability of radiated nucleus:

Assertion  :   An electric field is preferred in comparison to magnetic field for detecting the electron beam in a television picture tube.
Reason      :  Electric field require low voltage.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

Whenever a stream of electrons collides with a stream of photons, in this collision, which of the following is not conserved?

A circular coil of mean radius of 7 cm and having 4000 turns is rotated at the rate of 1800 revolutions per minute in the earth's magnetic field (B = 0.5 gauss), the maximum e.m.f. induced in coil will be(a) 1.158 V(b) 0.58 V(c) 0.29 V           (d) 5.8 V 

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

To increase both the resolving power and magnifying power of a telescope: