ECAT Pre Engineering Physics Chapter 12 MCQ Test With Answer

One coulomb per second is equal to

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

Resistance of a conductor depends upon

• the quantity of current passing through it A
• the voltage applied between its end B
• its dimensions, physical state and nature of its material C
• all 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

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

The liquid which conduct current is known as

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

• 5μF A
• 10μF B
• 3μF C
• 6μF 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

A capacitor is charged with a battery and then it is disconnected. A slab of dielectric is now inserted between the plates, then

• The charge in the plates reduces and potential difference increase A
• Potential difference between the plates increase, stored energy decreases and charge remains the same B
• Potential difference between the plates decreases and charge remains unchanged C
• None of the above D

Solar cell converts sunlight directly into

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

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

The relation V = IR represents

• Ampere law A
• Faraday's law B
• Ohm's law C
• Len's law D

Heating effect caused by an electric circuit is written

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

When an electron is accelerated through a P.D. of an one volt, it will acquire energy equal to

• One joule A
• One erg B
• One electron volt C
• None of these D

Consider a spherical shell of metal at he centre of which a positive point charge is kept

• The electric filed is zero outside the shell A
• The electric field is zero everywhere B
• The electric field is zero in the region inside the shell C
• The electric field is non-zero in both regions outside and inside the shell D

When a dielectric material is introduced between the plates of a charged condenser the electric field between the plates

• Decreases A
• Increases B
• No change C
• May increase or decresase D

The resistance of a conductor does not depend on its

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

The minimum charge on any object can not be less than

• 1.6 x 10^-19C A
• 3.2 x 10^-19C B
• 1.0 C C
• 4.8 x 10^-19C D

The force between two chares 0.06 m apart is 5 N. If each charge is moved towards the other by 0.01 m, then the force between them will become

• 7.20 N A
• 11.25 N B
• 22.50 N C
• 45.00 D

The potential difference across each resistance in series combination is

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

A cube of metal is given a positive charge Q. For the above system, which of the following statements is true?

• Electric potential at the surface of the cube is zero A
• Electric potential within the cube is zero B
• Electric filed is normal to the surface of the cube C
• Electric filed varies within the cube 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

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

Which one of the following has larger value of relative permitivity E_rat room temperature?

• Vaccum A
• Air B
• Glass C
• Water 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

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 energy stored in a charge capacitor

• 1/2CV² A
• 1/2C²V B
• 1/2C/V² C
• None of these 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

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