ECAT Pre Engineering Physics Chapter 12 MCQ Test With Answer

The electric flux from a closed surface

• Is independent of the shape of the surface A
• Depends on the charge enclosed by the surface B
• Both a and b C
• None of the above D

Three resistance 500,500 and 50 ohms are connected in series across 555 volts mains. The current flowing through them will be

• 0.52 A A
• 1 mA B
• 0.7 mA C
• 1.4 A D

A 50 volt battery is connected across 10 ohm resistor. The current is 4.5 A. The internal resistance of the battery is

• Zero A
• 0.5Ω B
• 1.1Ω C
• 5.0Ω D

Electric flux is defined by the relation

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

A car battery has e.m.f 12 volt and internal resistance 5 x 10^-2ohm. If it draws 60 ampere current, the terminal voltage of the battery will be

• 5 volt A
• 3 volt B
• 15 volt C
• 9 volt D

The current through a metallic conductor is due to the motion of

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

A 60 W bulb operates on 220 V supply. The current flowing through the bulb is

• 11/3 A A
• 3 A B
• 3/11 A C
• 6 D

Some charge is being given to a conductor. Then its potential

• Is maximum at surface A
• Is maximum at centre B
• Is remain same throughout the conductor C
• Is maximum somewhere between surface and centre 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 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 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

A parallel plate capacitor is first charged and then a dielectric slab is introduced between the plates. The quantity that remains unchanged is

• Charge Q A
• Potential V B
• Capacity C
• Energy U D

Resistance of a conductor is increased, the currant will

• Decrease A
• Increase B
• Remain the same C
• None 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

In a Milikian's oil drop experiment the charge on an oil drop is calculated to be 6.35 x 10^-19C. The number of excess electrons on the drop is

• 3.9 A
• 4 B
• 4.2 C
• 6 D

The liquid which conduct current is known as

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

The graphical representation of ohm's law is

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

In a voltmeter the conduction takes place due to

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

Three resistors of resistance R each are combined in various ways. Which of the following cannot be obtained?

• 3RΩ A
• 2R/4Ω B
• R/3Ω C
• 2R/3Ω D

The force of repulsion between two point charges is F, when these are at a distance 0.1 m apart. Now the point charges are replaced by sphere of radii 5 cm each having the same charge as that of the respective point charges. The distance between their centre is again kept 0.1 m ; then the force of repulsion will

• Increase A
• Decrease B
• Remain F C
• Become 10F/9 D

If a 40 watt light bulb burns for 2 hours. how much heat is generated

• 288 x 10³J A
• 288 x 10⁸J B
• 288 x 10⁵J C
• 288 x 10⁶J D

Calculate the amount of charge flowing in 2 minutes in a wire of resistance 10Ωwhen a potential difference of 20 V is applied between its ends

• 120 C A
• 240 C B
• 20 C C
• 4 C D

• 5μF A
• 10μF B
• 3μF C
• 6μF 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

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

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

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

At any point on the right bisector of the line joining two equal and opposite charges

• At electric field is zero A
• The electric potential is zero B
• The electric potential decreases with increasing distance from the centre C
• The electric field is perpendicular to the line joining the charges D

One moving a charge of 20 coulombs by 2 cm, 2 J of work is done, then the potential difference between the points is

• 0.1 V A
• 8 V B
• 2 V C
• 0.5 V D

The relation between the charge Q of a parallel plate capacitor and the P.D between its plates is

• Q=V/C A
• Q=C/V B
• Q=1/2CV C
• Q=CV D