Ohms law MCQ

Ohm’s law gives the relation between current, voltage and resistance. Ohm’s law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

Ohm’s law formula is written as;

V ∝ I

Therefore, V = RI where R is a constant called resistance. R depends on the dimensions of the conductor and also on the material of the conductor. Its SI unit is Ohm (Ω).

Q1: If a current of 5 Amperes flows through the conductor. The number of electrons per second will is

  1. 1.6 x 10-19
  2. 3.12 x 1019
  3. 4 x 1019
  4. 7.68 x 1020

Answer: (b) 3.12 x 1019

Q2: Ohm’s law is true for

  1. Metallic conductors at low temperature
  2. Metallic conductors at high temperature
  3. For electrolytes, when current passes through them
  4. For diode when current flows

Answer: (a) Metallic conductors at low temperature

Q3: An example of non-ohmic resistance is

  1. Diode
  2. Tungsten wire
  3. Carbon resistance
  4. Copper wire

Answer: (a) Diode

Q4: In a conductor, if 6-coulomb charge flows for 2 seconds. The value of electric current will be

  1. 3 ampere
  2. 3 volts
  3. 2 amperes
  4. 2 volts

Answer: 3 amperes

Q5: An EMF source of 8.0 V is connected to a purely resistive electrical appliance. An electric current of 2.0 A flows through it. What is the resistance offered by the electrical appliances?

  1. 4 ohm
  2. 6 ohm
  3. 2 ohm
  4. 3 ohm

Answer: (a) 4 ohm

Q6: A potential difference of 10 V is applied across a conductor whose resistance is 2.5 ohm. What is the value of current flowing through it?

  1. 4 amperes
  2. 2 amperes
  3. 6 amperes
  4. 10 amperes

Answer: (a) 4 amperes

Q7: If the conductor resistance is 50 ohm and the current passing through it is 5 A. What is the value of potential difference?

  1. 150 V
  2. 250 V
  3. 50 V
  4. 15 V

Answer: (b) 250 V

Q8: When the length of the conductor is doubled and the area of cross-section remains the same then its resistance

  1. Remains the same
  2. Will be doubled
  3. Will become half
  4. Will increase by four times

Answer: (b) Will be doubled

Q9: The current passing through a resistor in a circuit is 1 A when the voltage across the same resistor is 10 V. What is the value of current when the voltage across the resistor is 8 V

  1. 0.8 A
  2. 8 A
  3. 80 A
  4. 18 A

Answer: (a) 0.8 A

Q10: Two resistors R1 and R2 with resistance 5 ohms and 10 ohms respectively are connected in series. The voltage across R1 is 4 V. What will be the value of current across R2.

  1. 0.8 A
  2. 8 A
  3. 80 A
  4. 18 A

Answer: (a) 0.8 A


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