Electric Current (Physics) Part-I

Total Questions: 50

11. The total resistance of a circuit having two parallel resistors is 1.403 kilo-ohm. If one of the resistors is 2.0 kilo-ohm, then the other resistor will be [66ᵗʰ B.P.S.C. (Pre) 2020]

Correct Answer: (d) 4.70 kilo-ohm
Solution:

12. Of the two bulbs in a house, one glows brighter than the other. In this context which of the following statements is correct? [U.P. Lower Sub. (Pre) 2008, U.P.P.C.S. (Pre) 2009]

Correct Answer: (d) The dim bulb has larger resistance.
Solution:

13. Of the two bulbs in a house, one glows brighter than the other. Which of the two has a larger resistance ? [U.P.P.C.S. (Mains) 2013]

Correct Answer: (a) The dim bulb
Solution:

14. How two identical bulbs should be connected to get maximum light? [U.P.R.O./A.R.O. (Pre) 2021]

1. Both are connected in series.

2. Both are connected in parallel.

Select the correct answer using the code given below:

Code:

Correct Answer: (b) In case 2 more
Solution:

Bulbs in parallel are brighter than bulbs in series. In a parallel circuit the voltage for each bulb is the same as the voltage in the circuit while the parallel combination of resistors reduces the effective resistance of the circuit. The power dissipated by a bulb is given by

p = V²/R,

where V is the voltage of the light bulb and R is the electrical resistance.

15. A voltage of 15 volt is applied across a colour coded carbon resistor with first, second and third rings of brown, green and black colours. What is the current flowing through the resistor? [U.P.R.O/A.R.O. (Pre) 2023]

Correct Answer: (c) 1 ampere
Solution:

Resistor code value for brown colour = 1 (A)
Resistor code value for green colour = 5 (B)
Resistor code value for black colour = 0 (C)

We know that first two bands (rings) indicate the first two significant digits of resistance value and the third band serves as a multiplier.

So, Resistance value of resistor = (A × 10 + B) × 10ᶜ
= (1 × 10 + 5) × 10⁰
= 15 × 1 = 15 Ohm (Ω)

Current (i) = Voltage (V) / Resistance (R)

= 15 / 15 = 1 ampere

Hence, the current flowing through the resistor is 1 ampere.

16. A dynamo which is said to generate electricity actually acts as a: [U.P.P.C.S. (Mains) 2009]

Correct Answer: (c) Converter of energy
Solution:

A dynamo, which is also known as an electrical generator produces direct current through a commutator. It is basically a device which converts mechanical rotation into electric current according to Faraday's law.

17. 'Dynamo' is a device, which converts: [U.P. P.C.S. (Pre) 1992-94, 2016, 39ᵗʰ B.P.S.C. (Pre) 1994]

Correct Answer: (c) Mechanical energy into electrical energy
Solution:

A dynamo is an electrical generator that produces direct current with the use of a commutator. It converts mechanical energy into electrical energy.

18. Dynamo is a machine which is used for- [U.P.P.C.S. (Mains) 2012, R.A.S./R.T.S.(Pre) 2012]

Correct Answer: (c) Conversion of mechanical energy to electrical energy
Solution:

A dynamo is an electrical generator that produces direct current with the use of a commutator. It converts mechanical energy into electrical energy.

19. Turbines and Dynamos are used to convert which energy to electrical energy? [44ᵗʰ B.P.S.C. (Pre) 2000]

Correct Answer: (c) Mechanical energy
Solution:

A dynamo is an electrical generator that produces direct current with the use of a commutator. It converts mechanical energy into electrical energy.

20. When electrical energy is converted into motion [47ᵗʰ B.P.S.C. (Pre) 2005]

Correct Answer: (a) There is no heat loss
Solution:

When electrical energy is converted into motion, there is no heat loss.