For a ray incident from a denser to rarer medium, what is the critical angle of incidence it?

The northern lights and the aurora occurs in which of the following layers of atmosphere?

what position of the image is formed by the lens combination?

If:{ is the wavelength of the signal, then what should be the minimum size of the antenna so that it properly senses the time variation of the signal?

Which of the following options is the correct value of the refractive index of water?

Which of the following types of biasing is used in Zener diode?

Fast-moving currents of air that occur above the friction layer are called _____.

A 1 kg balloon at equilibrium in the air is buoyed up with a force of __________.

Henri becquerel and the curies found out that _____.

To say that an atom is excited is to say it has boosted _________.

A total completeness constraint is represented by _____.