Atomic and Nuclear Physics — Physics STD 12 Science — Question

A positively charged particle projected towards east is deflected towards north by a magnetic field. The field may be:

The diffraction effect can be observed in(a) Only sound waves(b) Only light waves(c) Only ultrasonic waves (d) Sound as well as light waves

The electric field at a point on equatorial line of a dipole and direction of the dipole moment:

Assertion :  The film which appears bright in reflected system will appear dark in the transmitted light and vice-versa.
Reason     : The conditions for film to appear bright or dark in reflected light are just reverse to those in the transmitted light.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

Half life of a radio-active substance is 20 minutes. The time between 20% and 80% decay will be(a) 20 minutes(b) 40 minutes(c) 30 minutes(d) 25 minutes

Television signals on earth cannot be received at distances greater than 100 km from the transmission station. The reason behind this is that(a) The receiver antenna is unable to detect the signal at a distance greater than 100 km(b) The TV programme consists of both audio and video signals(c) The TV signals are less powerful than radio signals(d) The surface of earth is curved like a sphere

Light waves exhibit polarization but sound waves do not exhibit polarization because they are not:

Two ions have equal masses but one is singly-ionised and the other is doubly-ionised. They are projected from the same place in a uniform magnetic field with the same velocity perpendicular to the field.

1. Both ions will move along circles of equal radii.
2. The circle described by the singly-ionised charge will have a radius that is. double that of the other circle.
3. The two circles do not touch each other.
4. The two circles touch each other.

Which of the following is the most suitable material for making permanent magnet?

When cathode rays (tube voltage ~ 10 kV) collide with the anode of high atomic weight then we get(a) Positive rays(b) X-rays(c) Gamma rays(d) Canal rays