ECAT Pre Engineering Physics Chapter 12 MCQ Test With Answer

A charge of 0.1 c accelerated through a potential difference of 1000V acquires kinetic energy

• 200 J A
• 100 J B
• 1000 J C
• 400 J D

A wire is bent into a ring of radius R is given a charge q. The magnitude of the electrical field at the centre of the ring is

• Two A
• 1/2 B
• Zero C
• 3/2 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

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

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

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 current through a metallic conductor is due to the motion of

• protons A
• neutrons B
• electrons C
• free electrons D

The electric lines of force are

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

The speed of randomly moving electrons depends upon

• pressure A
• volume B
• temperature C
• mass D

The conventional current in a circuit is defined as " current which passes from a point at higher potential to a point at lower potential as if it represent a movement of

• negative charges A
• positive charges B
• protons C
• electrons D

The resistance of the given conductor can be increased by

• Increasing the area A
• Changing resistivity B
• Decreasing the length C
• None of the above because change does not matter because in any case the volume remains 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

• 5μF A
• 10μF B
• 3μF C
• 6μF 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

Electron volt is the unit of.

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

For two resistance wires joined in parallel, the resultant resistance is 6/5 ohm. When one of the resistance wire breaks, the effective resistance becomes 2 ohm. The resistance of the broken wire is

• 3/5 ohm A
• 2 ohm B
• 6/5 ohm C
• 3 ohm 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

The concept of field theory was put forward by

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

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

In a charged capacitor the energy is stored in

• Both in positive and negative charges A
• Positive charges B
• The edges of the capacitor plates C
• The electric field between the plates 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

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 SI unit of electric flux is

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

The unit of conductance is

• ohm A
• meter B
• mho C
• ohm-meter 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

The minimum resistance that can be obtained by connecting 5 resistance of 1/4Ωeach is

• 4/5Ω A
• 5/4Ω B
• 20Ω C
• 0.05 Ω D

A heater coil rated at (1000 W - 200 V) is connected to 110 volt line. What will be the power consumed?

• 200 W A
• 302.5 B
• 250 W C
• 350 W D

The SI unit of conductivity is

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