physics Mcqs
701. If the volume of a gas is held constant and we increase its temperature then_______________?
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A. its pressure is constant

B. any of above

C. its pressure falls

D. its pressure rises
705. The audio signals of TV are _____________?
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A. Frequency modulated

B. Velocity modulated

C. Amplitude modulated

D. fixe modulated

706. The unit of power is _________?
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A. watt

B. Joule

C. Pascal

D. Newton

708. A ball is thrown towards the earth and bounce back. During this process:
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A. Direction of Displacement and Velocity changes

B. Direction of Displacement and acceleration changes

C. Direction of Displacement, Velocity and acceleration changes

D. Direction of velocity and acceleration changes

710. Reflecting mirrors in laser is used to______________?
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A. For producing more energetic lasers

B. Further stimulation

C. Lasing more

D. All

712. We prefer mercury as a thermometric substance because______________?
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A. It opaque to light

B. Over a wide range of temperature its expansion is uniform

C. It does not stick to thermometer glass

D. All of above
713. The scales of temperature are based on two fixed points which are_________________?
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A. The temperatures of ice cold and boiling water

B. The temperatures of frozen and boiling mercury

C. The temperatures of water at 0? 100?C

D. The temperature of melting ice and boiling water at atmospheric pressure
714. A photostat machine works on _____________?
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A. electrostatic image making

B. thermal image making

C. magnetic image making

D. electromagnetic image making

715. Petrol engine is a________________?
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A. all the above

B. C.I engine

C. IC engine

D. SI engine

716. In full wave rectification the output D.C. voltage across the load is obtained for_____________?
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A. All of the above.

B. The negative half cycle of input A.C.

C. The positive half cycle of input A.C.

D. The complete cycle of input A.C.
718. The owl can see most clearly in total darkness because:
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A. it has squint eyes

B. it has light bulbs in its eyes provided by nature

C. it produces infrasonic sounds

D. it has large eyes with orbs directed forward, giving it binocular sight
719. X-rays are diffracted by a crystal but not by a diffraction grating because_____________?
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A. The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal

B. The lines in a diffraction grating cannot reflect X-rays.

C. The penetration power of X-rays is high in a diffraction grating

D. The ions in a crystal are well arranged

720. Radiation produced from TV picture tube is_____________?
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A. X-rays

B. Far infrared

C. Infrared

D. B-rays

721. When X-rays are passed through successive aluminum sheets what happens to their thickness ?
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A. sometimes increases and sometimes decreases

B. it decreases

C. increases

D. it remains same
723. For the successful operation of Heat engine which condition should be met ?
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A. cyclic process

B. operated at certain temperature difference

C. both A and B

D. none of these

724. Tesla is the unit for measuring:
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A. Magnetic intensity

B. Magnetic induction

C. Magnetic moment

D. None of the above

725. The rectangular voltage is an example of____________________?
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A. Continuous wave form

B. An analogue waveform

C. Electronic waveform

D. A digital waveform
726. The synopsis of Einsteins equation E = mc is that
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A. The faster you move, the heavier you get

B. None of the above

C. The faster you move, the lighter you get

D. The slower you move, the heavier you get

728. A bird sitting on a high tension electric wire does not get electrocuted because:
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A. the body is earthed

B. it does not form a closed path for the flow of current

C. Sit has high resistance

D. its feet are good insulators

730. Neutron was discovered by: _________?
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A. Einstein

B. Neil Bohr

C. Chadwick

D. Rutherford

731. Wave-like characteristic of electron is demonstrated by______________?
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A. Photoelectric effect

B. Line spectrum of atoms

C. Production of x-rays.

D. Diffraction by crystalline solids
732. Which of the following is true ?
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A. Paschen series is a line spectrum in the infra red.

B. the spectral series formula can be derived from the Rutherford model of the hydrogen atom.

C. Lyman series is a continuous spectrum.

D. Balmer series is a line spectrum in the ultraviolet.

734. The working of transistor as amplifier is similar to________________?
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A. Step up transformer

B. Three diodes in common

C. Step down transformer

D. Triode vacuum tube
735. Standard condition STP refer to a gas at ___________________?
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A. 760mm 273K

B. 1atm 273K

C. all of the above

D. 76cm 0C

736. In p-n-p transistor the collector current is________________?
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A. greater than emitter current

B. equal to emitter current

C. any of above

D. slightly less than emitter current
737. The power is the dot product of ___________ quantities.
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A. None of these

B. Force and speed

C. Force and velocity

D. Force and time

738. An OP-AMPs can amplify_______________?
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A. D.C.

B. A.C.

C. Both A.C. & D.C.

D. None of the above

739. Two parallel beams of positrons moving in the same direction will________?
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A. not interact with each other

B. attract each other

C. be deflected normal to the plane containing the two beams.

D. repel each other
740. The internal energy of the system increases__________?
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A. in isothermal expansion

B. in adiabatic expansion

C. in adiabatic compression

D. in isothermal compression

741. Newtons Third Law of Motion?
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A. every action there is an equal and opposite reaction.

B. temperature remaining constant, volume of a given mass of a gas varies inversely

C. volume of a given mass of gas increases or decreases

D. attraction or repulsion between two charges

743. The electronic circuits which implement the various logic operations are called_____________?
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A. Logic functions

B. Boolean algebra

C. Logic gates

D. Amplifier gain

744. In forward bias the width of potential barrier_____________?
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A. Decreases

B. Remains same

C. Increases

D. No effect

745. Joule Thomson effect is based upon __________ ?
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A. Sudden compression of gases

B. Cooling of gases

C. Sudden expansion of gases

D. Heating of gases

747. Which one of the following has the greatest energy gap ?
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A. insulator

B. any of above

C. conductor

D. semi conductor

749. A million electron are added to a pith ball. Its charge is________?
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A. 1.6 1013 coulomb

B. 1.6 10 coulomb

C. 1.6 10 <sup>18</sup> coulomb

D. 1.6 10<sup>12</sup> coulomb