MCQ – Basic Electrical – Set I

1. The ratio of voltage and electric current in a closed circuit

  • remains constant
  • varies
  • increases
  • falls

2. The curve representing ohm’s law is

  •  sine function
  • Linear
  • A parabola
  • a hyperbola

3. The resistance of a conductor having length l area of cross section a and resistivity ρ is given as:

  • ρa/l
  • ρl/a
  • ρla
  • l/ρa

4. The resistance of wire varies inversely as

  •  area of cross section
  • length
  • resistivity
  • temperature

5. Which of the following quantities are same in all parts of a series circuit?

  • voltage
  • power
  • current
  • resistance

6.Which of the following statements is false in case of a series circuit?

  • the voltage drop across each resister is same
  • the current flowing through each resistor is the same
  • applied voltage is equal to the sum of voltage drops across individual resistors
  • resistors are additive

7. A resistance of 30 Ω is connected across 240v supply. If a resistance R Ω is connected in parallel   with 30Ω resistor across the same supply, the current drawn becomes triple of original one. The unknown resistor R is

  • 15Ω
  • 10Ω
  • 5Ω
  • 30Ω

8. Three resistors, each of R ohms, are connected to form a triangle. The resistance between any two terminals will be:

  • 2/3 R
  • 3/2R
  • R
  • 3R

9. Which of the following is not correct?

  • P=V/R^2
  • P=VI
  • I=√(P/R)
  • V=√PR

10. A 100W bulb is connected in series with a room heater. If now 100W bulb is replaced by a 40w bulb, the heater output will :

  • increase
  • decrease
  • Remain the same

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