Electricity

81.___ is equal to one volt?
 
A. 1 joule
 
B. 1 joule/coulomb
 
C. 1 newton/coulomb
 
D. 1 joule/newton
 
Option “B” is correct.
82.When a soap bubble is charged, then-
 
A. It contracts
 
B. It expands
 
C. There is no change in its shape
 
D. None of the above
 
Option “B” is correct.
When a soap bubble is charged then it expands to decrease the surface Tension, i.e. to minimize the surface tension.
83.Dynamo is a machine whose job is
 
A. Converting high voltage to low
 
B. Converting low voltage to high
 
C. Convert electrical energy into mechanical energy
 
D. Convert mechanical energy into electrical energy
 
Option “D” is correct
84.A current carrying conductor is associated with –
 
A. From the magnetic field
 
B. From electric field
 
C. From the electromagnetic field
 
D. From electrostatic field
 
Option “C” is correct.
A current carrying conductor, such as a metal wire, will produce a magnetic field around it because of the motion of charge within the wire itself. This motion produces or sets up a magnetic field around the wire in the form of concentric circles. This electromagnetic effect is described in physics by the Biot-Savart Law, an experimentally deduced inverse-square law. The effect is also described by Ampere’s Law, which is derived from the Biot-Savart Law.
85.Which instrument measures electrical resistance?
 
A. Ammeter
 
B. Potentiometer
 
C. Voltmeter
 
D. Ohm meter
 
Option”D” is correct.

  • The ratio of the potential difference between the ends of a resistor to the current flowing through it is called its electrical resistance.
  • It is measured in ‘ohms’.
  • An ohmmeter is an electrical device used to measure resistance.

Additional Information

  • Ammeter –
    • It is an instrument for measuring the current flowing in a branch of a circuit.
  • Voltmeter –
    • It is a measuring instrument used to measure the potential difference between any two points of a circuit.
  • Galvanometer –
    • It is a kind of ammeter only.
    • It is used to detect the presence of current in a circuit.

86.When a glass rod is rubbed with silk, the rod-
 
A. Gains electrons from silk
 
B. Gives electrons to silk
 
C. Gains protons from silk
 
D. Gives protons to silk
 
Option “B” is correct.
On rubbing glass rod with silk, excess electron transferred from glass to silk. So glass rod becomes positive and silk becomes negative.
87.Where do charges reside in the case of a charged conductor?
 
A. Inside the conductor
 
B. On the outer surface of the conductor
 
C. On the inner surface of the conductor
 
D. Anywhere outside the conductor
 
Option “B” is correct.
Since the electric field is zero inside the conductor, the mutual repulsion of like charges from Coulomb’s Law demands that the charges be as far apart as possible. Hence on the surface of the conductor, the net electric charge of a conductor resides entirely on its surface.
88.The force between two electric charges is related to__
 
A. Ampere’s law
 
B. Coulomb’s law
 
C. Faraday’s law
 
D. Rules of OM
 
Option “B” is correct.
According to Coulomb’s law, the force of attraction or repulsion between two charged bodies is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.
89.If the distance between two electric charges is halved, then the value of electric force between them will be
 
A. Half
 
B. Double
 
C. Four times
 
D. One fourth
 
Option”C” is correct
90.When two bodies have similar charges are kept close to each other, then they will:
 
A. Repel each other
 
B. Attract each other
 
C. Neither attract nor repel
 
D. Can’t say
 
Option “A” is correct

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