Electric Charges and Fields — Physics STD 12 Science — Question

By what speed do electromagnetic waves travel in vacuum?

When electrons drift in a metal from lower to higher potential, does it mean that all the free electrons of the metal are moving in the same direction?

A concave lens of refractive index 1.5 is immersed in a medium of refractive index 1.65. What is the nature of the lens?

When a solid melts or a liquid boils, the temperature does not increase even when heat is supplied. Where does the energy go?

Answer the following question:
In what way is diffraction from each slit related to the interference pattern in a double-slit experiment?

A capacitor has capacitance C. Is this information sufficient to know what maximum charge the capacitor can contain? If yes, what is this charges? If no, what other information is needed?

Can a metal sphere of radius 1 em be given a charge of IC?

When a body is weighed on an ordinary balance we demand that the arm should be horizontal if the weights on the two pans are equal. Suppose equal weights are put on the two pans, the arm is kept at an angle with the horizontal and released. Is the torque of the two weights about the middle point (point of support) zero? Is the total torque zero? If so, why does the arm rotate and finally become horizontal?

When a charged particle moves in a magnetic field normally; what quantity changes the particle’s speed, particle’s energy, path of motion of the particle?