Quiz: 12th Grade Physics Practice Paper!
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- 1.What would be the electric flux due to two charges one at the origin of the Gaussian sphere and another at a distance of 4b from origin. Let the radius of the Gaussian sphere be 3b and the charge be Q.
- A.
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- B.
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- C.
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- D.
0
- 2.What happens to mutual inductance of pair of coils when distance between the coils is increased:
- A.
Mutual Inductance of first coil will increase with decrease in second coil
- B.
Mutual Inductance of both the coils increases
- C.
Mutual Inductance of both the coils decreases
- D.
Mutual Inductance of second coil will increase with decrease in first coil
- 3.For a semiconductor a negative resistance could found during a:
- A.
Negative Slope
- B.
Positive Slope
- C.
Constant Slope
- D.
Variable Slope
- 4.What would be the current through the resistance which is connected to three voltage source connected in parallel to each other:
- A.
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- B.
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- C.
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- D.
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- 5.What is the reason for the damping of copper plate when it is allowed to oscillate in between the two magnetic poles:
- A.
Polarisation
- B.
Eddy Current
- C.
Amplitude Modulation
- D.
Stationary Waves
- 6.What is the S.I. Unit of Radioactivity:
- A.
Newton
- B.
Curie
- C.
Becquerel
- D.
Joule
- 7.Welders wear special goggles to protect their eyes from:
- A.
Ultraviolet Rays
- B.
Infrared Rays
- C.
Microwaves
- D.
Cosmic Rays
- 8.De Broglie waves associated with a football is not visible because:
- A.
Velocity of the football
- B.
Weight of the football
- C.
Density of the football
- D.
Mass of the football
- 9.When does a transistor act as a switch:
- A.
Collector current is kept constant
- B.
Collector current is increases
- C.
Collector current is zero
- D.
Collector current decreases
- 10.What is used to converge the light beam at a single point on the screen during diffraction:
- A.
Polaroid
- B.
Converging Lens
- C.
Diverging Lens
- D.
Prism
- 11.When a dielectric medium is introduced in between a capacitor, the capacitance:
- A.
Increases
- B.
Decreases
- C.
Constant
- D.
Becomes Negative
- 12.If the capacitor is being charged by an external ac source with an instantaneous current of I0 cos ωt. The displacement current would be:
- A.
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- B.
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- C.
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- D.
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- 13.In which phenomenon the electrons move with an average velocity which is independent of time, although the electrons are accelerated:
- A.
Resistivity
- B.
Photoelectric Effect
- C.
Drift Velocity
- D.
Interference
- 14.For drift velocity the electrons move from:
- A.
Low potential to high potential
- B.
High potential to low potential
- C.
Negative potential to zero potential
- D.
Positive potential to zero potential
- 15.A potentiometer is not affected by the internal resistance of the source because:
- A.
The internal resistance of a given cell is fixed
- B.
One of the cells is chosen as a standard cell whose emf is known to a high degree of accuracy
- C.
To maintain a steady current
- D.
It draws no current from the voltage source being measured
- 16.The air bubble inside water acts as a _____ lens
- A.
Diverging or Concave
- B.
Plane Mirror
- C.
Converging or Convex
- D.
Bi-Convex
- 17.A+B = Y denotes which Gate:
- A.
NAND Gate
- B.
OR Gate
- C.
NOR Gate
- D.
AND Gate
- 18.The condition for maximum power dissipation is:
- A.
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- B.
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- C.
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- D.
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- 19.What would be the resistance of the light bulb rated at 100 W for 220 V ac supply:
- A.
280 Ω
- B.
465 Ω
- C.
382 Ω
- D.
484 Ω
- 20.What will happen if an open circuit is used in place of the closed loop?
- A.
Flux is induced at the centre of the circuit
- B.
Flux is induced at only one of the ends of the circuit
- C.
Flux is induced across the open ends of the circuit
- D.
Flux is induced for a short period of time
- 21.If £ is the emf induced between axle and the rim of a wheel. What is the effect on emf if number of spokes were increased?
- A.
Emf is doubled
- B.
No change in Emf
- C.
Emf becomes half
- D.
Emf becomes 4 times
- 22.Device used only to check the flow of current in a circuit:
- A.
Voltmeter
- B.
Wheatstone Bridge
- C.
Potentiometer
- D.
Galvanometer
- 23.Current is flowing from east to west in a wire AB. What would be the direction of the flow of current in a wire CD parallel to AB:
- A.
East to West
- B.
North to South
- C.
West to East
- D.
South to North
- 24.Name the semiconductor device which works under the reverse bias condition:
- A.
Solar Cell
- B.
Zener Diode
- C.
Transistor
- D.
Microprocessor
- 25.In a diode, what happens at critical voltage:
- A.
Zener Breakdown
- B.
Saturation Current Flow
- C.
Avalanche Breakdown
- D.
Recombination of Charges Occur
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