ECAT Pre Engineering Physics Chapter 12 MCQ Test With Answer

A condenser of capacity 50μF is charged to 10 V.The energy stored is

• 1.25 x 10^-3J A
• 3.75 x 10^-3J B
• 2.5 x 10^-3J C
• 5 x 10^-3J 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 intensity at a point due to a point charge

• Falls off inversely as the distance A
• Falls off inversely as the square of distance B
• Remains unchanged with distance C
• Increase directly as square of distance D

Ohm established a relation between

• voltage and resistance A
• voltage and charge B
• voltage and current C
• voltage resistance and charge 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

One joule is equal to

• 1.6 x 10¹⁹eV A
• 6.25 x 10¹⁸eV B
• 1.6 x 18¹⁸eV C
• 6.25 x 10¹⁹eV D

• 5μF A
• 10μF B
• 3μF C
• 6μF D

The fractional change in resistance per kelvin is known as

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

The graphical representation of ohm's law is

• hyperbola A
• straight line B
• ellipse C
• parabola 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

The charge carriers in gases are

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

If one volt is needed to cause a current of one ampere to flow in a conductor, its resistance is

• one ohm A
• one joule B
• one volt C
• one ampere 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

The conductivity of a superconductor is

• Infinite A
• Very large B
• Very small C
• Zero D

A proton is about 1840 times heavier than an electron. When it is accelerated by a potential difference of 1 KV, its kinetic energy will be

• 1840 KeV A
• 1/1840 KeV B
• 1 KeV C
• 920 KeV 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

If we plot graph between potential difference (V) and current (I) obeying ohm's law, it will give us

• parabola A
• straight line B
• hyper bola C
• ellipse D

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

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

Heating effect caused by an electric circuit is written

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

Two point charges A and B separated by a distance R attract each other with a force of 12 x 10^-3N. The force between A and B when the charges on them are doubled and distance is halved

• 1.92 N A
• 19.2 N B
• 12 N C
• 0.192 N D

If the length of the conductor is double and its cross sectional area is halved, its conductance will

• Increase four fold A
• Become one-fourth B
• Become one-half C
• Remains unchanged D

The resistance of a conductor does not depend on its

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

Solar cell converts sunlight directly into

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

Physicist George Simon ohm was a

• German physical A
• French physicist B
• Chinese physicist C
• Russian physicist 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

Electric potential of earth is taken to be zero because the earth is good

• Semiconductor A
• Conductor B
• Insulator C
• Dielectric D

The electrode connected with the positive terminal of the current source is called

• cathode A
• anode B
• electrolyte C
• position D

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

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