ECAT Pre Engineering Physics Chapter 12 MCQ Test With Answer

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

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

The resistance of a conductor does not depend on its

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

A charge Q is divided into two parts q and Q - q and separated by a distance R. The force of repulsion between them will be maximum when

• q = Q/4 A
• q = Q/2 B
• q = ! C
• None of these D

In bringing an electron towards another electron, electrostatic potential energy of system

• Decreases A
• Increases B
• Remains uncharged C
• Becomes zero D

A current of 1.6 A is passed through a solution of CuSO_{4. How many Cu}²⁺ions are liberated in one minute?

• 3 x 10²⁰ A
• 3 x 10¹⁰ B
• 6 x 10²⁰ C
• 6 x 10¹⁰ D

Thermocouple is an arrangement of two different metals

• To convert heat energy in to electrical energy A
• To produce more heat B
• To convert heat energy into chemical energy C
• To convert electric energy in to heat energy 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 SI unit of conductivity is

• ohm-m A
• ohm^-1m^-1 B
• ohm-m^-1 C
• ohm^-1m D

If the resistance of 2 ohm and 4 ohm are connected in parallel, the equivalent resistance will be

• 6 ohm A
• 4 ohm B
• zero ohm C
• 1.33 ohm D

Ohm's law states that

• The current through a resistor is directly proportional to the applied voltage A
• The voltage across a resistor is directly proportional to the current passing through it B
• Resistance is the constant of proportionality between the voltage and current C
• all of these D

The potential difference across the conductors should be maintained constant by connecting the ends of wire to the terminal of a device called a source of

• power A
• current B
• resistance C
• temperature 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

A certain charge liberates 0.8 g of oxygen. The same charge will liberate. how many g of silver?

• 108 g A
• 10.8 g B
• 0.8 g C
• 108/0.8 g 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

• 5μF A
• 10μF B
• 3μF C
• 6μF D

The SI unit of current is

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

Free electrons are

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

A capacitor of capacity 1μF is charged to 1 KV. The energy stored in J

• 5 A
• 0.5 B
• 0.005 C
• 50 D

The relation V = IR represents

• Ampere law A
• Faraday's law B
• Ohm's law C
• Len's law 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

The fractional change in resistance per kelvin is known as

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

One coulomb per second is equal to

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

The dot product of electric field intensity E and vector area A is called

• Electric potential A
• Electric flux B
• Electric field C
• Magnetic field D

Two electric bulbs of 200 W and 100 W have same voltage. If R₁and R₂be their resistance respectively then

• R₁= 2R₂ A
• R₂= 2R₁ B
• R₂ = 4R₁ C
• R₁= 4R₂ D

Electron volt is the unit of.

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

A ten ohm electric heater operates on a 110 V line. Calculate the rate at which it develops heat in watts

• 1310 W A
• 670 W B
• 810 W C
• 1210 W D

The capacity of a parallel plat capacitor depends on the

• Type to metal used A
• Thickness of plates B
• Potential applied across the plates C
• Separation between the plates 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

Battery is charged in motor cars, which is based on

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