Nuclei — Physics STD 12 Science — Question

With what Hertz produced electro-magnetic waves?

Why does the energy of emitted photo-electrons vary even after shining light on the surface of a metal?

Name the physical quantity which remains same for microwaves of wavelength 1mm and UV radiations of 1600 Å in vacuum.

What is the resultant force on an electric dipole placed in a uniform electric field?

How much work will be required to bring a test charge q, one em along the equatorial axis of an electric dipole?

State any two factors responsible for energy loss in practical transformer.

Answer the following questions, which help you understand the difference between Thomson’s model and Rutherford’s model better.

Keeping other factors fixed, it is found experimentally that for small thickness t, the number of α-particles scattered at moderate angles is proportional to t. What clue does this linear dependence on t provide?

A circular loop of radius 4.0cm is placed in a horizontal plane and carries an electric current of 5.0A in the clockwise direction as seen from above. Find the magnetic field:

1. At a point 3.0cm above the centre of the loop.
2. At a point 3.0cm below the centre of the loop.

Select one donor impurity from the following : Boron (B), Aluminum (Al) and Arsenic (As).