ECAT Pre General Science Physics Chapter 12 MCQ Test With Answer

Force acting upon a charged particle kept between the plates of a charged condenser if F. IF one of the plates of the condenser is removed, force acting on the same will become

• Zero A
• F/2 B
• F C
• 2F D

Magnetic effect at a point caused due to flow a current depend upon the

• Quantity of current A
• Distance from current B
• Both the quantity of current and distance from current element C
• None of the all D

Three resistors of resistance R each are combined in various ways. Which of the following cannot be obtained?

• 3RΩ A
• 2R/4Ω B
• R/3Ω C
• 2R/3Ω D

The capacitance of a parallel plate capacitor depends upon

• Area of the plates A
• Separation between the plates B
• Medium between the plates C
• All of the above D

The resistance of a conductor does not depend on its

• mass A
• resistivity B
• length C
• cross-sectional area D

• 5μF A
• 10μF B
• 3μF C
• 6μF D

Free electrons are

• tightly bound A
• fixed B
• loosely bound C
• tightly fixed D

Resistance of a conductor depends upon

• the quantity of current passing through it A
• the voltage applied between its end B
• its dimensions, physical state and nature of its material C
• all of the above D

The value of electrical constant of proportionality k is

• 9 x 10⁹Nm²C^-2 A
• 9 x 10^-9Nm²C^-2 B
• 9 x 10¹⁰Nm²C² C
• 9.85 x 10^-12N^-1C^-2 D

The powers of tow electric bulbs are 100 W and 200 W. Both of them are joined with 220 V mains. The ratio of resistances of their filaments will be

• 1 : 2 A
• 2 : 1 B
• 1 : 4 C
• 4 : 1 D

A wire of radius r has resistance R. If it is stretched to a wire of r/2 radius, then the resistance becomes

• 2R A
• 4R B
• 16R C
• Zero D

Resistance of a conductor is increased, the currant will

• Decrease A
• Increase B
• Remain the same C
• None of these D

Cause of heat production in a current carrying conductor is

• Collisions of free electrons with one another A
• High drift speed of free electrons B
• Collisions of free electrons with atoms or ions of conductor C
• High resistance value D

The SI unit of current is

• watt A
• coulomb B
• volt C
• ampere D

Battery is charged in motor cars, which is based on

• Chemical effect A
• Magnetic effect B
• Electric effect C
• None D

The relation between charge 'Q' and current 'I' is given by

• Q = I/t A
• Q = It B
• Q = I²t C
• Q = I²/t D

The statement "the electric force of repulsion or attraction between two point charges is directly proportional to the product of the charges and inversely proportional to square of the distance between them" refer to

• Coulomb's law A
• Gauss's law B
• Biot-Sarwat law C
• Ampere's law D

The electric lines of force are

• Imaginary A
• Physically existing everywhere B
• Physically existing near the charge C
• All of the above D

If we increase the distance between two plates of the capacitor, the capacitance will

• Increase A
• Decrease B
• Remain same C
• First increase then decrease D

The liquid which conduct current is known as

• heating effect A
• chemical energy B
• electrolyte C
• ohm's law D

An electric charge at rest is

• Only an electric field A
• Only a magnetic field B
• Both electric and magnetic fields C
• None of the above D

Some charge is being given to a conductor. Then its potential

• Is maximum at surface A
• Is maximum at centre B
• Is remain same throughout the conductor C
• Is maximum somewhere between surface and centre D

If two bulbs one of 60 W and other of 100 W are connected in parallel, then which one of the following will flow more?

• 60 W bulb A
• 100 W bulb B
• Both equally C
• None of these D

The unit of resistance is

• volt A
• ampere B
• ohm C
• coat D

Capacitance of two or more capacitors

• Increases in series combination A
• Increases in parallel combination B
• Remains unchanged C
• None of the above D

Coulomb's force between two point charges depends upon

• Magnitude of charges A
• Distance between them B
• Medium in which they are located C
• All of the above D

The charge carriers in electrolyte are positive and negative

• protons A
• electrons B
• ions C
• none of these D

A capacitor is charged with a battery and then it is disconnected. A slab of dielectric is now inserted between the plates, then

• The charge in the plates reduces and potential difference increase A
• Potential difference between the plates increase, stored energy decreases and charge remains the same B
• Potential difference between the plates decreases and charge remains unchanged C
• None of the above D

Which of the following does not obey ohm's law?

• Copper A
• Al B
• Diode C
• None D

If the distance between the plates of a parallel plate condenser of capacity 10μF is doubled then new capacity will be

• 5μF A
• 20μF B
• 10μF C
• 15μF D