ECAT Pre Engineering Physics Chapter 12 MCQ Test With Answer

The electric intensity at infinite distance from the point charge will be

• Infinite A
• Positive B
• Zero C
• Negative D

The material in the form of wire or rod or plate which leads the current into or cut of the electrolyte is known as

• voltmeters A
• resistance B
• electrode C
• current D

The liquid which conduct current is known as

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

In RC series circuit the time during which the capacitor acquires 0.63 times the equilibrium charge is called

• Time constant A
• Decay constant B
• None of these C
• All of above D

The earth's potential is taken as

• Negative A
• Positive B
• Zero C
• 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

Solar cell converts sunlight directly into

• potential energy A
• thermal energy B
• mechanical energy C
• electrical energy D

The resistivity of a substance depends upon the

• length A
• mass B
• area C
• temperature D

The thermistors are usually made of

• Metals with low temperature coefficient of resistivity A
• Metals with high temperature coefficient of resistivity B
• Metal oxides with high temperature coefficient of resistivity C
• Semi conducting materials having low temperature coefficient of resistivity D

The SI unit of permitivity is

• Nm²C² A
• N^-1m^-2C² B
• NmC² C
• Nm²C^-1 D

The SI unit of electric flux is

• Weber A
• Nm²C^-1 B
• NmC^-1 C
• Nm^-2C D

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

• 64 W A
• 80 W B
• 100 W C
• 125 W D

• 5μF A
• 10μF B
• 3μF C
• 6μF D

Free electrons are

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

One electron volt is equal to

• 1.6 x 1019eV A
• 6.25 x 1018 eV B
• 1.6 x 1018 eV C
• 6.25 x 1019eV D

In a voltmeter the conduction takes place due to

• Electrons only A
• Holes only B
• Electrons and holes C
• Electrons and ions D

One coulomb per second is equal to

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

The resistance of 20 cm long wire is 10Ω. When the length is changed to 40 cm. The new resistance is

• 10Ω A
• 20Ω B
• 30Ω C
• 40Ω D

A 10 F capacitor is charged to a potential difference of 50 V and is connected to another uncharged capacitor in parallel. Now the common potential difference becomes 20 volt.The capacitance of second capacitor is

• 10μF A
• 20μF B
• 30μF C
• 15μF 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

Heating effect caused by an electric circuit is written

• H = I²Rt A
• H = I²R B
• H = IR²t C
• H = IR² 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

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

The ratio of the gravitational force F_gto the electrostatic force F_ebetween two electrons at the same distance apart is approximately

• 9.8 A
• 24 x 10¹⁹ B
• 24 x 10⁴² C
• 24 x 10^-44 D

What is the current is a 2 x 10⁶ohm resistor having a potential difference of 2 x 10³volts?

• 10^-1A A
• 10^-2A B
• 10^-4A C
• 1 mA D

An alpha particle is accelerated through a potential difference of 10⁶volt. Its kinetic energy will be

• 1 MeV A
• 2 MeV B
• 4 MeV C
• 8 MeV 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

Which of the following represents an electric current?

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

Electric flux is defined by the relation

• E.A. A
• E x A B
• E/A C
• none of these D

The SI unit of current is

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