Q. Define the following: Thermionic Emission and Dual Nature of Radiation.

Q. In a compound microscope the focal length of objective lens.

1. Is equal to the focal length of eyepiece lens
2. Is more than the focal length of eyepiece lens
3. Is less than the focal length of eyepiece lens
4. Is two times to the focal length of eyepiece lens

Q. Establish the formula for intensity of magnetic field at the centre of a current carrying circular coil.

Q. What is parallax? Explain.

Q. The specific resistance of a wire depends upon the

1. Length
2. Diameter
3. Mass
4. Material

Q. Why the Ozone layer is important for existence of life on the Earth?

Q. The planck's constant is $h$ and frequency of a photon is $\nu$ then write the formula for Einstein photo electric equation.

Q. The ultraviolet radiant bulbs are made of quartz. Not of glass. Why?

Q. State Brewster's law. Prove that if light is incident at the angle of polarization the reflected and refracted rays are mutually perpendicular.

Q. Write any four the necessary conditions for interference of light.

Q. Which type of semi-conductor is formed when a trivalent impurity is dopped in a pure semiconductor?

Q. The number of photo electrons emitted per second depend on the ____________ of incident radiatic.

Q. Which substance is used as depolarizer in Leclanche cell?

Q. Zener-diode is used in.

1. Rectification
2. Amplification
3. Oscillator in producing oscillations
4. Volatge regulation

Q. Write the relation between focal length and radius of curvature of a spherical mirror?

Q. What is population inversion and optical pumping? Explain.

Q. Write Faraday's laws of electromagnetic induction and obtain an expression of induced e.m.f.

Q. With increase in temperature of a semiconductor its conductivity ___________.

Q. What is the effect on self inductance of a solenoid, if a core of soft iron is placed in it?

Q. Blue colour of sky is due to __________.

Q. Establish the formual of intensity of magnetic field due to a bar magent in the equatorial position.

Q. The value of angle of dip at magnetic poles of the Earth is ___________.

Q. Write any four differences between step-up and step-down transformer.

Q. The waves used in telecommunication are.

1. Ultraviolet
2. Infra red
3. Micro waves
4. Cosmic rays

Q. What is matter waves? Write any two characteristics of it.

Q. The dielectric constant of air is.

1. $8.85\times {10}^{-12}{C}^2{N}^{-1}{M}^{-2}$
2. Zero
3. $1$
4. Infinite

Q. Time period of geostationary satellite is ____________ hours.

Q. What is conjugate foci? Explain.

Q. Select the appropriate option from column 'B' for each statement of column 'A' and match the correct pair.

Q. What is optical fiber? On what principle does it work?