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 45 of 53
- A. 25 W bulb
- B. 100 W bulb
- C. First 20 W and then 100 W bulb
- D. Neither bulb will glow
Explanation: When two bulbs are connected in series, the same current flows through both bulbs.
Correct answer: 25 W bulb- A. 1011
- B. 1016
- C. 1019
- D. 1015
Explanation: I=1.6mA=1.6×10−3Since the charge on the electron is: e=1.6×10−19C, t=1s So, N=eI =eqt Where N is the number of electrons flowing per…
Correct answer: 1016- A. 4.5 Ω
- B. 2 Ω
- C. 0.5 Ω
- D. 1/4.5 Ω
Explanation: The internal resistance of a cell can be calculated using the formula r = E/I, where E is the electromotive force (emf) and I is the…
Correct answer: 0.5 Ω- A. Copper
- B. Tungsten
- C. Germanium
- D. Aluminium
Explanation: Germanium is a semi conductor and it has negative temperature coefficient of resistance.
Correct answer: Germanium- A. R1 = R0(1 +αt)
- B. R1 = R0 (1-αt)
- C. R1=R02(l+αt)
- D. R1=R02(1-αt)
Explanation: .Rt = Ro(1 + α∆T) is the formula for the relationship between resistance and temperature.
Correct answer: R1 = R0(1 +αt)- A. 2.5 x 10 19
- B. 1.25 x 10 13
- C. 2.5 x 10 20
- D. 6 x 10 8
Explanation: = 6.02 x 1023x 4/96500=2.5 x 1019 electrons.
Correct answer: 2.5 x 10 19- A. Positive
- B. Zero
- C. Negative
- D. Constant
Explanation: When an emf is traversed from + to − (opposite to the direction it moves positive charge), the change in potential is - emf.
Correct answer: Negative- A. Area of cross-section
- B. Length
- C. Nature of material of conductor
- D. Both length and area
Explanation: Resistivity is a material property of the conductor. It depends only on the temperature of the conductor and not on the length or density…
Correct answer: Nature of material of conductor- A. Collision of metal atoms with each other releases heat energy
- B. Collision of conduction electrons with each other releases heat energy
- C. Collision of conduction electrons with the atoms of metal give them energy which appears as heat
- D. All of these
Explanation: .Temperature is defined as the measure of average kinetic energy in the system.
Correct answer: Collision of conduction electrons with the atoms of metal give them energy which appears as heat- A. 12W
- B. 15W
- C. 20W
- D. 18W
Explanation: efficiency = output/input × 100output = (efficiency × input)/100output = 12W
Correct answer: 12W891. The substances which have a large number of free electrons and offer a low resistance are called:
- A. Insulators
- B. Semi-conductors
- C. Inductors
- D. Conductors
Explanation: Conductors are substances that have a large number of free electrons, and they offer very low resistance.
Correct answer: Conductors- A. Copper
- B. Carbon
- C. Aluminum
- D. Brass
Explanation: The correct answer is option B: Carbon. Carbon can exhibit a negative temperature coefficient of resistance, meaning that its resistance…
Correct answer: Carbon- A. E
- B. E/2
- C. Zero
- D. E/3
Explanation: The correct option is: c) Zero. When a cell is short-circuited, the current flows with minimum resistance directly between its terminals…
Correct answer: Zero- A. 0.5 Ω
- B. 1.0 Ω
- C. 1.2 Ω
- D. 2.0 Ω
Explanation: Let E be the emf of the cell and r be the internal resistance.here, E = 0.9(2+r)...(1) and E = 0.3(7+r)...(2)From (1) and (2), 0.9(2+r) =…
Correct answer: 0.5 Ω- A. 0.1 A
- B. 0.5 A
- C. 1.5 A
- D. 2.0 A
Explanation: Potential Difference across the 15 ohm resistor is 7.5V,V = IRI = V/R = 7.5/15 = 0.5A
Correct answer: 0.5 A- A. Electrodes of the cell
- B. Vessel of the cell
- C. Electrode used in the cell
- D. Electrolyte
Explanation: The correct option is: d) Material used in the cell:This option is the correct answer.
Correct answer: Electrolyte- A. 0.8 X 10 -17 A
- B. 8 x 10^-17 A
- C. 0.4 x 10^-17 A
- D. 80 x 10^-17 A
Explanation: The current associated with a circulating electron can be calculated with the formula I = Qf, where Q is the charge of an electron…
Correct answer: 0.8 X 10 -17 A- A. Positve and negative ions
- B. Negative ions and electrons
- C. Electrons and holes
- D. Positive ions and electron
Explanation: D is correct. Only positive ions and electrons act as charge carriers in gas.
Correct answer: Positive ions and electron- A. Resistance
- B. Conductance
- C. Emf
- D. Capacitance
Explanation: B is correct. The slope is 1/R which is known as conductance.
Correct answer: Conductance- A. Current
- B. Power
- C. Resistance
- D. Both "A" and "B"
Explanation: According to Ohm's law voltage is directly proportional to current. Double voltage, we give double current.
Correct answer: Current