Electromagnetic Waves — Physics STD 12 Science — Question

Consider a small surface area of 1mm² at the top of a mercury drop of radius 4.0mm. Find the force exerted on this area:

1. By the air above it.
2. By the mercury below it and.
3. By the mercury surface in contact with it. Atmospheric pressure = 1.0 × 10⁵Pa and surface tension of mercury = 0.465N/m. Neglect the effect of gravity. Assume all numbers to be exact.

Depict the behaviour of magnetic field lines in the presence of a diamagnetic material.

Calculate the minimum energy needed to separate a neutron from a nucleus with Z protons and N neutrons it terms of the masses M_Z.N, M_Z,N-1 and the mass of the neutron.

A cube of iron (density = 8000kg m^-3, specific heat capacity = 470J kg^-1 K^-1) is heated to a high temperature and is placed on a large block of ice at 0°C. The cube melts the ice below it, displaces the water and sinks. In the final equilibrium position, its upper surface just goes inside the ice. Calculate the initial temperature of the cube. Neglect any loss of heat outside the ice and the cube. The density of ice = 900kg m^-3 and the latent heat of fusion of ice = 3.36 × 10⁵J kg^-1.

A metallic bob A oscillates through the space between the poles of an electromagnet. The oscillations are more quickly damped when the circuit is on, as compared to the case when the circuit is off. Explain.

What is the value of I in the given current distribution?

Write the value of electric flux due to a point charge located outside the surface of a sphere.

Answer the following questions:
The earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km). What agencies may be responsible for this distortion?