Magnetism — Physics STD 12 Science — Question

In a cathode ray tube, what is the effect on the beam of particles if a hotter filament is used?

Which of the following cannot be seen by a microscope?

The collector plate in an experiment on photoelectric effect is kept vertically above the emitter plate. Light source is put on and a saturation photocurrent is recorded. An electric field is switched on which has a vertically downward direction.

1. The photocurrent will increase.
2. The kinetic energy of the electrons will increase.
3. The stopping potential will decrease.
4. The threshold wavelength will increase.

Work done to bring a unit positive charge from infinity to a point in an electric field is known as _______?

The final image is formed in a compound microscope will be :

An alpha particle moving with an initial velocity (uj)enters a region of uniform magnetic field B=Bk. the de-Broglie wavelength of the alpha particle.

‘X’ is a substance which does not allow the flow of charges through it but permits them to exert electrostatic forces on one another through it. Identify X.