For a CE-transistor amplifier, the audio signal voltage across the collector resistance of is 2V. Given the current amplification factor of the transistor is 100, find the input signal voltage and base current, if the base resistance is

A. A radioactive nucleus ‘A’ undergoes a series of decays as given below :

The mass number and atomic number of are 176 and 71 respectively. Determine the mass and atomic numbers of and A.

B. Write the basic nuclear processes underlying and decays.

A. A ray of light incident on face AB of an equilateral glass prism, shows minimum deviation of 30^o. Calculate the speed of light through the prism.

B. Find the angle of incidence at face AB so that the emergent ray grazes along the face AC.

Describe the working principle of a moving coil galvanometer. Why is it necessary to use (i) a radial magnetic field and (ii) a cylindrical soft iron core in a galvanometer? Write the expression for current sensitivity of the galvanometer.

Can a galvanometer as such be used for measuring the current? Explain.

OR

A. Define the term ‘self-inductance’ and write its S.I. unit.

B. Obtain the expression for the mutual inductance of two long co-axial solenoids and would one over the other, each of length L and radii and and and number of turns per unit length, when a current I is set up in the outer solenoid

Mrs. Rashmi Singh broke her reading glasses. When she went to the shopkeeper to order new specs, he suggested that she should get spectacles with plastic lenses instead of glass lenses. On getting the new spectacles, she found that the new ones were thicker than the earlier ones. She asked this question to the shopkeeper but he could not offer satisfactory explanation for this. At home, Mrs. Singh raised the same question to her daughter Anuja who explained why plastic lenses were thicker.

A. Write two qualities displayed each by Anuja and her mother.

B. How do you explain this fact using lens maker’s formula?