Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

What is the magnitude of alternating emf from peak to peak?

Define the unit of electric potential.

A capillary tube of radius 0.50mm is dipped vertically in a pot of water. Find the difference between the pressure of the water in the tube 5.0cm below the surface and the atmospheric pressure. Surface tension of water = 0.075N/m.

A ball is dropped on a floor from a height of 2.0m. After the collision it rises up to a height of 1.5m. Assume that 40% of the mechanical energy lost goes as thermal energy into the ball. Calculate the rise in the temperature of the ball in the collision. Heat capacity of the ball is 800JK^-1.

Why should electrostatic field be zero inside a conductor?

Consider the situation described in the previous problem. Suppose the current i enters the loop at the point A and leaves it at the point B. Find the magnetic field at the centre of the loop.

An experimenter measures the length of a rod. Initially the experimenter and the rod are at rest with respect to the lab. Consider the following statements:

1. If the rod starts moving parallel to its length but the observer stays at rest, the measured length will be reduced.
2. If the rod stays at rest but the observer starts moving parallel to the measured length of the rod, the length will be reduced.

1. Is true but B is false.
2. B is true but A is false.
3. Both A and B are true.
4. Both A and B are false.

A cylindrical object of outer diameter 20cm and mass 2kg floats in water with its axis vertical. If it is slightly depressed and then released, find the time period of the resulting simple harmonic motion of the object.

Write any two examples of paramagnetic substances.

A photographic plate placed at a distance of 5cm from a weak point source is exposed for 3s. If the plate is kept at a distance of 10cm from the source, the time needed for the same exposure is:

1. 3s
2. 12s
3. 24s
4. 48s