Semiconductor Electronics: Materials, Devices and Simple Circuits — Physics STD 12 Science — Question

Work done in moving a positive charge on an equipotential surface is(a) Finite, positive but not zero(b) Finite, negative but not zero(c) Zero(d) Infinite

Image of any object formed at the retina of human eye is :

In a discharge tube at 0.02 mm, there is a formation of(a) FDS(b) CDS(c) Both space(d) None of these

An oxide coated filament is useful in vacuum tubes because essentially(a) It has high melting point(b) It can withstand high temperatures(c) It has good machanical strength(d) It can emit electrons at relatively lower temperatures

X-ray beam can be deflected:

A dip circle is taken to geomagnetic equator. The needle is allowed to move in a vertical plane perpendicular to the magnetic meridian. The needle will stay:

1. In horizontal direction only.
2. In vertical direction only.
3. In any direction except vertical and horizontal.
4. In the direction it is released.

When light travels from one medium to the other of which the refractive index is different, then which of the following will change(a) Frequency, wavelength and velocity(b) Frequency and wavelength(c) Frequency and velocity(d) Wavelength and velocity

A transistor is used in common emitter mode as an amplifier. Then(a) The base-emitter junction is forward biased(b) The base-emitter junction is reverse biased(c) The input signal is connected in series with the voltage applied to the base-emitter junction(d) a, c