Physics : PRE Medical Entrance Question Bank
(Paper - 4)

1. Sun releases energy by the process of
A. nuclear fusion
B. nuclear disintegration
C. nuclear fission
D. spontaneous combustion



2. The number of atoms per unit cell in a sc, bcc, and fcc are
A. 1, 2 and 4 respectively
B. 8, 6 and 10 respectively
C. 1, 4 and 2 respectively
D. 2, 4 and 1 respectively



3. In a diode, at saturation current, the plate resistance is
A. zero
B. constant and finite
C. infinite
D. variable but finite



4. An n-type and a p-type silicon semi-conductor can be obtained by doping pure silicon with
A. sodium and magnesium respectively
B. phosphorous and boron respectively
C. indium and sodium respectively
D. boron and arsenic respectively



5. When the plate voltage of a triode is 150 V, its cut off voltage is -5 V. On increasing the plate voltage to 200 V, the cut off voltage can be
A. -4.5V
B. -5.0V
C. + 2.3 V
D. -6.06 V



6. In a diode vacuum tube, the plate current is 5 mA when the plate voltage is 160 V. A grid is introduced between the plate and cathode and a voltage of -2 V is applied to it. The plate current then become
A. 20 mA
B. 10 mA
C. 4mA
D. 7.5mA



7. A long spring is stretched by 2cm. Its potential energy is V. If the spring is stretched by 10cm, its potential energy would be
A. V/25
B. V/5
C. 5V
D. 25V



8. The length of a rod as measured by an observer moving with respect to it is half of its proper length. The speed of the observer with respect to rod is
A. 3/2 c ms-1
B. c/2 ms-1
C. (Ö3)/2 c ms-1
D. 1/Ö2 c ms-1



9. A + m -meson with a proper half-life of 1.8 x 10-6 s is moving with a speed of 0.9 c with respect to an earth observer. The half-life of this m -meson according to an observer sitting on it is
A. 1.8 x 10-6 s
B. 1.8 x Ö0.19 x 10-6 s
C. 1.8/Ö0.19 x 10-6 s
D. 1.8 x 0.19 x 106 s

 

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