ECAT Pre Engineering Physics Chapter 12 MCQ Test With Answer

The ohm's is defined as

• 1 ampere / 1 volts A
• 1 coulomb / 1 volt B
• 1 volt / 1 ampere C
• 1 volt / 1 coulomb D

The potential difference across each resistance in series combination is

• same A
• different B
• zero C
• none of these D

A metal plate of thickness half the separation between the capacitor plates of capacitance C is inserted. The new capacitance is

• C A
• C/2 B
• Zero C
• 2C D

• 5μF A
• 10μF B
• 3μF C
• 6μF D

The concept of field theory was put forward by

• Franklin A
• Kepler B
• Oersted C
• Michael Faraday D

A cube of metal is given a positive charge Q. For the above system, which of the following statements is true?

• Electric potential at the surface of the cube is zero A
• Electric potential within the cube is zero B
• Electric filed is normal to the surface of the cube C
• Electric filed varies within the cube 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

The unit of resistance is

• volt A
• ampere B
• ohm C
• coat D

The minimum charge on any object can not be less than

• 1.6 x 10^-19C A
• 3.2 x 10^-19C B
• 1.0 C C
• 4.8 x 10^-19C D

A sheet of aluminium foil of negligible thickness is introduced between the plates of a capacitor. The capacitance of the capacitor

• Increases A
• Decreases B
• Remain unchanged C
• Becomes infinite D

Three resistors of resistance 2,3 and 6 ohms are connected in parallel, their equivalent resistance is

• 11.0 ohm A
• 1.0 ohm B
• 7.0 ohm C
• 3.0 ohm D

The fractional change in resistance per kelvin is known as

• temperature coefficient A
• resistance coefficient B
• super temperature C
• critical temperature D

Taking the earth to be a spherical conductor of diameter 12.8 x 10³km. Its capacity will be

• 711μF A
• 611μF B
• 811μF C
• 511μF D

Surface density of charge is defined as

• Charge per unit volume A
• Charge per unit length B
• Charge per unit area C
• Charge per unit mass D

The force between two chares 0.06 m apart is 5 N. If each charge is moved towards the other by 0.01 m, then the force between them will become

• 7.20 N A
• 11.25 N B
• 22.50 N C
• 45.00 D

Which of the following represents an electric current?

• C^-1 A
• CS^-1 B
• J.S^-1 C
• dynes^-1 D

When a dielectric material is introduced between the plates of a charged condenser the electric field between the plates

• Decreases A
• Increases B
• No change C
• May increase or decresase D

A (100 W , 200 W) bulb is connected to a 160 V power supply. The power consumption would be

• 64 W A
• 80 W B
• 100 W C
• 125 W D

If an electron of charge 'e' is accelerated through a potential difference V., it will acquire energy

• Ve A
• V/e B
• e/V C
• 2Ve D

Two conductors having the same type of charges are connected by a conducting wire. There would not be any amount of charges on them if

• They have the same potential A
• They have the same amount of charge B
• They have the same capacity C
• They have the same shape D

If the two charges in Coulomb's law have double distance between them, then electric force

• Becomes two-fold A
• Becomes four-fold B
• Remains the same C
• None of these D

If 2.2 kilowatt power is transmitted through 1 10 ohm line at 22000 volt, the power loss in the form of heat will be

• 0.1 watt A
• 1 watt B
• 10 watt C
• 100 watt 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

The electric field due to an infinite long thin wire at a distance R varies as

• 1/R A
• 1/R² B
• R C
• R² D

One coulomb per second is equal to

• One volt A
• One ampere B
• One hom C
• One henry D

A hollow insulated conduction sphere is given a positive charge of 10μC. What will be the electric field at the centre of the sphere if its radius is 2 meters?

• Zero A
• 5μC m^-2 B
• 20μC m^-2 C
• 8μC m^-2 D

If a 40 watt light bulb burns for 2 hours. how much heat is generated

• 288 x 10³J A
• 288 x 10⁸J B
• 288 x 10⁵J C
• 288 x 10⁶J D

The electric field will be uniform

• Near a positive point charge A
• Near a negative point charge B
• Between two oppositely charged parallel metal plates C
• None of above D

Electron volt is the unit of

• Potential difference A
• Energy B
• Resistance C
• Capacitance D

A uniform resistance wire of Length L and diameter d has a resistance R. Another wire of same material has length, 4L and diameter 2d, the resistance will be

• 2 R A
• R B
• R/2 C
• R/4 D