Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

In Davison-Germer experiment, an electron beam is incident on a crystal. The reflected beam consists of:

The cold junction of a thermocouple is maintained at 10℃. No thermo e.m.f. is developed when the hot junction is maintained at 530 ℃ . The neutral temperature is(a) 260℃(b) 270℃(c) 265℃(d) 520℃

A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence, the rod gains gravitational potential energy. The work required to do this comes from:

The number of turns in primary and secondary coils of a transformer are 100 and 300 respectively. If in- put power is 60 W, then output power will be:

An electron beam in an X-ray tube is accelerated through a potential difference of 50000 volts. These are then made to fall on a tungsten target. The shortest wavelength of the X-ray emitted by the tube is(a) 2.5 Å (b) 0.25 nm(c) 0.25 cm(d) 0.025 nm

Ionization potential of hydrogen atom is 13.6 V.
Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12.1 eV. The spectral lines emitted by hydrogen atoms according to Bohr's theory will be(a) One   (b) Two(c) Three(d) Four

A varying current in a coil change from 10A to 0 in 0.5sec. If the average emf induced in the coil is 220V, the self inductance of the coil is: