RPET 2008 Physics Sample Paper
1. The variation of angular
momentum with time for a rigid
body rotating about an axis is as
shown in the figure.
The torque at t = 40 seconds is :
(1) 1 Joule
(2) 1 Newton
(3) Zero
(4) 0.75 Joule
2. The Pendulum of a grand-father’s clock
swings 10 cm from side to side per
second. Assuming it to be a simple
pendulum, show that the peak velocity
of the bob (in cm/sec) is nearly :
(1) 16
(2) 12
(3) 8
(4) 4
3. Ball I having 1 kg mass strikes a
glancing blow to another ball II at rest
in an elastic collision with a speed of
5m/s. Ball I then moves off at right
angle to its initial direction at a speed of
4 m/s. The momentum of ball II after
collision in magnitude would be nearly :
(1) 5
(2) 6
(3) 1
(4) 2
4. For a gm molecule of hydrogen and
helium gases two specific heats (Cp and
Cv) are found. Choose the correct
statement concerning these specific
heats:
(1) The ratio Cp / Cv for both gases is
equal
(2) The ratio Cp / Cv for helium is more
than for hydrogen.
(3) The ratio Cp / Cv for hydrogen is
more than for helium
(4) The difference (Cp - Cv) for both is
Unequal
5. Two slits are placed 2 mm apart and
300 cm from the screen. When light of
6000 angstroms is used, the bright lines
of the interference pattern will be
separated by a distance in mm equal to :
(1) 3.1
(2) 4.15
(3) 0.90
(4) 9.00
6. Two locomotives moving with a speed
of 36 km/ hr recede from each other,
One of the locomotives whistles with a
frequency of 200 Hz. Taking velocity of
sound in air to be 340 m/s, the pitch of
whistle (in Hz) as heard by an observer
in the other locomotive will be :
(1) 188
(2) 212
(3) 200
(4) 224
7. What is the maximum charge (in
coulombs) that can be conveyed to a
conducting sphere of diameter 10 cm, if
the breakdown voltage of air. is 2 x 106
volts/m ?
(1) 2.0 x 10-4
(2) 5.6 x 10-7
(3) 5.6 x 10-2
(4) 2.0 x 102
8. In a potentiometer a long uniformly
thick resistance wire is used to have
(1) high resistance of potentiometer
(2) small heating of the wire
(3) high potential drop along the wire
(4) uniform and small potential gradient
9. Voltage of a power line at a given place
is 220V. The peak voltage (in volts)
will nearly be :
(1) 440
(2) 220
(3) 310
(4) 345
10. The wave length of first line of the
Lyman series of a ten times ionized Na
atom (Z = 11) is about (the first of the
Lyman series for hydrogen is 1216 Å or
1.216 x 10-7 m) :
(1) 0.1 Å
(2) 10 Å
(3) 103 Å
(4) l00 Å