ECAT Pre General Science Physics Chapter 12 MCQ Test With Answer

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

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

In a voltmeter the conduction takes place due to

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

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

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

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

The energy required to charge a capacitor of 5μF by connecting D.C. source of 20 KV is

• 10 KJ A
• 5 KJ B
• 2 KJ C
• 1 KJ D

If electric and gravitational force on an electron in a uniform electric field will be

• E=mg/q A
• E=q/mg B
• E=,g/q C
• E=qg/m 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

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

Capacitance of two or more capacitors

• Increases in series combination A
• Increases in parallel combination B
• Remains unchanged C
• None of the above D

Electric flux is defined by the relation

• E.A. A
• E x A B
• E/A 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

If the distance of separation between two chares is increased, the electrical potential energy of the system will

• Increase A
• Decrease B
• May increase or decrease C
• Remain the same 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

• 5μF A
• 10μF B
• 3μF C
• 6μF 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

The charge carriers in gases are

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

Electron volt is the unit of.

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

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

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

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

• cathode A
• anode B
• electrolyte C
• position 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

Electric generators which convert mechanical energy into

• solar energy A
• thermal energy B
• kinetic energy C
• electrical energy 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

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

Physicist George Simon ohm was a

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

The electric lines of force are

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

Battery is charged in motor cars, which is based on

• Chemical effect A
• Magnetic effect B
• Electric effect C
• None D