Free Current Electricity MCQs with Answers
1,052 Current Electricity MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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1,052 questions · page 46 of 53
- A. 150 Watt
- B. 100 watt
- C. 40 Watt
- D. All have same brighteness
Explanation: As they are connected in series so current across them will be same. the 40W bulb will hence experience less resistance than the other…
Correct answer: 40 Watt- A. 400oC
- B. 450oC
- C. 500oC
- D. 550oC
Explanation: The correct answer is C: 500oC. To solve this, apply the formula: Rt = R0(1 + αt), where α is the temperature coefficient of resistance.
Correct answer: 500oC- A. 3 : 2
- B. 2 : 3
- C. 3 : 4
- D. 4 : 3
Explanation: The correct answer is 3 : 2. The resistance of an electrical device is calculated using the formula R = V2/P, where R is resistance, V is…
Correct answer: 3 : 2- A. The other bulb continues to glow with the same brightness
- B. The other bulb stops glowing
- C. The other bulb glows with increased brightness
- D. The other bulb also burns out
Explanation: If there are two bulbs connected in series and one blows out, the other bulb will stop glowing.
Correct answer: The other bulb stops glowing- A. 600 J
- B. 1.2 x 10^3 J
- C. Depends on for how much time it is used
- D. 3.6 x 10^4 J
Explanation: The total energy stored in the 12V-50 Ampere-hour battery is 1200 Joules.
Correct answer: 1.2 x 10^3 J- A. Rs 136
- B. R 137
- C. Rs 138
- D. Rs 139
Explanation: New bulbs = 5, Old bulbs = 7: Total wattage of new bulbs = 5 × 50; Total wattage of old bulbs = 7 × 50: Time the new bulbs are kept on = 5…
Correct answer: Rs 138- A. Double
- B. Same
- C. Half
- D. One fourth
Explanation: Resistivity does not depend upon dimension (L,W) of wire. It only depends upon nature & temperature of wire.
Correct answer: Same908. A wire of resistance R is stretched four times its length uniformly. Its new resistance will be
- A. 16 R
- B. 4 R
- C. R/4
- D. R/16
Explanation: R = ρL/A L' = 4L ; A' = A/4 R' = ρ(4L) / (A/4) ==> R' = 16ρL / A R' / R = (16ρL / A ) / (ρL/A ) ==> R' / R = 16 R' = 16R
Correct answer: 16 R- A. Source of e.m.f
- B. Resistor
- C. Conductor
- D. Capacitor
Explanation: Internal resistance is the resistance offered by source of e.m.f.
Correct answer: Source of e.m.f- A. IRt
- B. I2Rt
- C. l2R
- D. Vlt
Explanation: The rate at which electrical energy is converted to heat is the power dissipated, P = I²R.
Correct answer: l2R- A. length = 100 cm, diameter = 1 mm
- B. length = 50 cm, diameter = 0.5 mm
- C. length= 200 cm, diameter= 2 mm
- D. length= 300 cm, diameter= 2 mm
Explanation: R= l/r2. For highest resistance, l/r2 should be maximum, which is correct for option B.
Correct answer: length = 50 cm, diameter = 0.5 mm- A. 5V
- B. 1.2V
- C. 0.9V
- D. 0.6V
Explanation: I = 1.5/3+ 2 = 1.5/5 Now V = IR = 1.5/5 × 3 = 0. 9V
Correct answer: 0.9V- A. 6.5 ohm
- B. 5 ohm
- C. 3 ohm
- D. 4 ohm
Explanation: The explanation for this question is as follows.
Correct answer: 3 ohm- A. watt × second
- B. volt × meter
- C. volt per couloumb
- D. Newton per meter
Explanation: The unit of power is the watt, and hence the unit of energy is watt-second since energy is the product of power and time.
Correct answer: watt × second- A. 1.6 x 10^-26 A
- B. 1.6 x 10^12 A
- C. 1.6 x 10^-12 A
- D. 107 A
Explanation: Q=10⁷×1.6×10−19 which is flowing per second in a conducting wire hence I=1. 6×10−12A
Correct answer: 1.6 x 10^-12 A- A. 25 W
- B. 100 watt bulb
- C. First 20W and then 100 W bulb
- D. Neither bulb will glow
Explanation: Resistance of 25 W bulb is R25 =V2/P=(220)2/25=1936Ω Resistance of 100 W bulb is R100 =V2/P=(220)2/100=484ΩAs both bulbs are in series…
Correct answer: 25 W- A. 4 : 25
- B. 2 : 5
- C. 25 : 4
- D. 5 : 2
Explanation: P = V2/R Bulb 1= 500W, 250V Bulb 2 = 200W, 250V Let's calculate, For Bulb 1.
Correct answer: 2 : 5- A. Length is doubled
- B. Length is trippled
- C. Length is doubled and radius is halved
- D. Length is halved and radius is doubled
Explanation: The correct option is: c) Length is doubled and radius is halved If the length of the wire is doubled (2L) and the radius is halved (R/2)…
Correct answer: Length is doubled and radius is halved- A. Electrodes of the cell
- B. Vessel of the cell
- C. Electrode used in the cell
- D. Material used in the cell
Explanation: The correct option is: d) Material used in the cell:This option is the correct answer.
Correct answer: Material used in the cell- A. Directly proportional to the area of cross-section
- B. Proportional to square of the area of cross-section
- C. Inversely proportional to the area of cross-section
- D. lndependent of the area of cross-section
Explanation: The charge passing through any cross-section per unit time is current and is inversely proportionaly to resistance and hence is directly…
Correct answer: Directly proportional to the area of cross-section