ECAT Pre General Science Physics Chapter 12 MCQ Test With Answer

The electric lines of force are

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

• 5μF A
• 10μF B
• 3μF C
• 6μF D

One coulomb per second is equal to

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

A point charge A of charge +4μC and another B of charge -1μC are placed in air at a distance 1 m apart. Then the distance of the point on the line joining the charge B, where the resultant electric field is zero, is (in m)

• 2 A
• 1 B
• 0.5 C
• 1.5 D

Force acting upon a charged particle kept between the plates of a charged condenser if F. IF one of the plates of the condenser is removed, force acting on the same will become

• Zero A
• F/2 B
• F C
• 2F 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

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

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

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

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

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

The powers of tow electric bulbs are 100 W and 200 W. Both of them are joined with 220 V mains. The ratio of resistances of their filaments will be

• 1 : 2 A
• 2 : 1 B
• 1 : 4 C
• 4 : 1 D

Magnetic effect at a point caused due to flow a current depend upon the

• Quantity of current A
• Distance from current B
• Both the quantity of current and distance from current element C
• None of the all D

Ohm is the unit of

• current A
• capacitance B
• energy C
• resistance 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

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 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

A certain charge liberates 0.8 g of oxygen. The same charge will liberate. how many g of silver?

• 108 g A
• 10.8 g B
• 0.8 g C
• 108/0.8 g D

Electric flux is defined by the relation

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

The resistance of an incandescent lamp is

• Smaller when switched on A
• Greater when switched off B
• The same whether it is switch off or switch on C
• Greater when switched on D

A current of 1.6 A is passed through a solution of CuSO_{4. How many Cu}²⁺ions are liberated in one minute?

• 3 x 10²⁰ A
• 3 x 10¹⁰ B
• 6 x 10²⁰ C
• 6 x 10¹⁰ 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

A metal plate of thickness half the separation between the capacitor plates of capacitance C is inserted. The new capacitance is

• C A
• C/2 B
• Zero C
• 2C 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

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

The electric field due to an infinite long thin wire at a distance R varies as

• 1/R A
• 1/R² B
• R C
• R² D

The SI unit of current is

• watt A
• coulomb B
• volt C
• ampere D

The graphical representation of ohm's law is

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

Potentiometer is more sensitive than voltmeter, because

• Voltmeter has a very high resistance A
• Voltmeter has a very low resistance B
• Potentiometer does not draw any current from a source of unknown potential difference C
• Potentiometer is sensitive D