ECAT Pre Engineering Physics Chapter 12 MCQ Test With Answer

The nature of capacity of electrostatic capacitor depends on

• Shape A
• Size B
• Thickness of plates C
• Area 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 resistivity of a substance depends upon the

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

If the distance of separation between two chares is increased, the electrical potential energy of the system will

• Increase A
• Decrease B
• May increase or decrease C
• Remain the same D

A closed surface contains two equal and opposite charges. The net electric flux from the surface will be

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

10⁶electrons are moving through a wire per second, the current developed is

• 1.6 x 10^-19 A
• 1 A B
• 1.6 x 10^-15 A C
• 10⁶A D

Two point charge +3μC and +8μC repel each other with a force of 40 N. If a charge of -5μC is added to each of them, then the force between then will become

• -10 N A
• +10 N B
• +20 N C
• -20 N 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

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

The charge carriers in electrolyte are positive and negative

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

The potential difference across each resistance in series combination is

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

• 5μF A
• 10μF B
• 3μF C
• 6μF D

The SI unit of electric field intensity is

• CN^-1 A
• NC^-1or Vm^-1 B
• JC^-1 C
• AV^-1 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

Solar cell converts sunlight directly into

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

Electron volt is the unit of.

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

Which one of the following causes production of heat when current is set up in a wire?

• Fall of electrons from higher orbits to lower orbits A
• Inter-atomic collisions B
• Inter-electron collisions C
• Collisions of conduction electron with atoms D

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

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

Coulomb force, when any material medium is placed between two charges

• Increases A
• Decreases B
• Remain unchanged C
• None of these D

An electron of charge e coulomb passes through a potential difference of V volts its energy in joules will be

• V/e A
• eV B
• e/V C
• V D

Current provided by a battery is maximum when

• Internal resistance equal to external resistance A
• Internal resistance is greater than external resistance B
• Internal resistance is less then external resistance C
• None of these D

One coulomb of charge is created by

• 10 electrons A
• 1.6 x 10^-19electrons B
• 6.25 x 10¹⁸electrons C
• 6.25 x 10²¹electrons 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

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

The charge carriers in gases are

• electrons A
• ions B
• protons C
• ions and electrons D

The electric potential at the surface of an atomic nucleus (Z = 50) of radius 9.0 x 10^-15 is

• 9 x 10⁵V A
• 9 V B
• 8 x 10⁶V C
• 80 V D

The unit of intensity of electric field is

• newton/coluomb A
• jule/coluomb B
• volt x metre C
• newton/metre D

Electric generators which convert mechanical energy into

• solar energy A
• thermal energy B
• kinetic energy C
• electrical energy D