Nuclei — Physics STD 12 Science — Question

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

Power factor of an ac circuit is 0.5. What is the phase difference between current and voltage in the circuit?

When the skeleton of an elephant and the skeleton of a mouse are prepared in the same size, the bones of the elephant are shown thicker than those of the mouse. Explain why the bones of an elephant are thicker than proportionate. The bones are expected to withstand the stress due to the weight of the animal.

A cubical block of wood weighing 200g has a lead piece fastened underneath. Find the mass of the lead piece which will just allow the block to float in water. Specific gravity of wood is 0.8 and that of lead is 11.3.

When a p-type impurity is doped in a semiconductor, a large number of holes are created. This does not make the semiconductor charged. But when holes diffluse from the p-side to the n-side in a p-n junction, the n-side gets positively charged. Explain.

Name the dielectric whose molecules have:

1. Non-zero,
2. Zero dipole moment.

Raindrops of radius 1mm and mass 4mg are falling with a speed of 30m/s on the head of a bald person. The drops splash on the head and come to rest. Assuming equivalently that the drops cover a distance equal to their radii on the head, estimate the force exerted by each drop on the head.

Write phase difference between applied emf and current in pure resistor, inductor and capacitor.

Write the ratio of the number of free electrons and holes in an intrinsic semiconductor.

What is the electric flux through a cube of side 1 cm which encloses an electric dipole?