1.

Which of the following statements are correct for a transistor action ?
(A) The input resistance depends upon the current I_C in the transistor
(B) Collector currents is equal to the sum of base current and emitter current
(C) The emitter junction is forward biased
(D) The collector junction is reverse biased
(E) Both the emitter junction as well as the collector junction are forward biased
Choose the correct answer from the options given below:

• (A), (B) and (C) only
• (B), (C) and (D) only
• (C), (D) and (E) only
• (A) and (C) only

2.

Which of the following statements are correct?
(A) The resistivity of a semiconductor decreases with increasing temperature.
(B) The potentiometer is unaffected by the internal resistance of the source.
(C) In ionic crystals and electrolytic liquids electrons carry the electric current.
(D) Ohm's law fails if V depends on I non-linearly.
(E) Kirchhoff's rules are used for analysis of electric circuits.
Choose the correct answer from the options given below:

• (B), (C) and (E) only
• (A), (B), (D) and (E) only
• (C), (D) and (E) only
• (A), (C) and (D) only

3.

A radioactive isotope phosphorous-32 has an initial activity 10μCi and has half life of 14 days. What is the activity of the source after 42 days?

• 1.25μCi
• 2.5μCi
• 5μCi
• 0.625μCi

4.

"The congress was reluctant to include the demands of industrial workers in its program of struggle." analyze the reasons.

5.

Energy band gap is maximum in:

• metals
• semi-conductor
• super conductor
• insulator

6.

A vertical electric field of magnitude 4.9×10⁵ NC^-1 just prevents a water droplet of mass 0.1 g from falling. What is the charge on the droplet? Take acceleration due to gravity 9.8 ms^-2.

• 2.0×10^-9 C
• 2.0×10^-6 C
• 5.0×10⁵ C
• 5.0×10⁶ C