For a photoconductor with equal electron and hole mobilities and perfect ohmic c

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Question
For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in intensity of optical illumination results in
Options
A. a change in o.c voltage
B. a change in s.c current
C. decrease in resistance
D. increase in resistance

Correct Answer

decrease in resistance

Explanation

It is the characteristic of a photoconductor that its resistance decreases with increase in illumination.

Materials and Components problems

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2. If q is charge on an electron, R is radius of electron orbit and ? is angular velocity of electron rotation, the magnetic dipole moment of electron in orbit is
Options
A. 0.5 q?R
B. 0.5 q²?²R²
C. 0.5 q?R²
D. 0.5 q?²R

3. Assertion (A): Copper is a monoatomic solid.
Reason (R): In a metal the valence electrons belong to all atoms.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

5. Assertion (A): CO₂ has no resultant dipole moment but CO has a dipole moment.
Reason (R): The structure of CO₂ is O = C = O.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

6. Assertion (A): If W_F is Fermi energy, v is velocity of electron and m is mass of electron, then .
Reason (R): Conductivity of a metal depends on temperature and impurity concentration.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

7. The temperature below which certain materials are antiferromagnetic and above which they are paramagnetic is called
Options
A. Weiss temperature
B. Curie temperature
C. Neel temperature
D. None of the above

8. Assertion (A): When cathode temperature is increased from 2500 K to 2550 K, thermionic emission current may increase by about 50%.
Reason (R): Thermionic emission current ? T² e^-Ew/kT.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

9. Assertion (A): Silicon is the most favoured semiconductor material.
Reason (R): PIV for silicon diode is more than that for germanium diode.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

10. Assertion (A): Magnetism can be explained by the theory of magnetic domains.
Reason (R): The existence of magnetic domains is evident from the Bitter powder patterns.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

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