Magnetism and Matter — Physics STD 12 Science — Question

The weight of a body at the poles is greater than the weight at the equator. Is it the actual weight or the apparent weight we are talking about? Does your answer depend on whether only the earth's rotation is taken into account or the flattening of the earth at the poles is also taken into account?​​​​​

The half-life of a radioisotope is 10h. Find the total number of disintegrations in the tenth hour measured from a time when the activity was 1Ci.

1. Define the term ‘intensity of radiation’ in terms of photon picture of light.
2. Two monochromatic beams, one red and the other blue, have the same intensity. In which case (i) The number of photons per unit area per second is larger, (ii) The maximum kinetic energy of the photoelectrons is more? Justify your answer.

1. Name two important processes that occur during the formation of a pn junction.
2. Draw the circuit diagram of a full wave rectifier along with the input and output waveforms. Briefly, explain how the output voltage/current is unidirectional.

In a Geiger - Marsden experiment, calculate the distance of closest approach to the nucleus of Z = 80, when an α-particle of 8 MeV nergy impinges on it before it comes momentarily to rest and reverses its direction.
How will the distance of closest approach be affected when the kinetic energy of the α-particle is doubled?

A cyclotron’s oscillator frequency is 10 MHz. What should be the operating magnetic field for accelerating protons? If the radius of its ‘dees’ is 60 cm, calculate the kinetic energy (in MeV) of the proton beam produced by the accelerator.