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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- A. Current
- B. Electrical energy
- C. Power
- D. Voltage
Explanation: A watt-hour (Wh) is a unit of energy; it's a way to measure the amount of work performed or generated.
Correct answer: Electrical energy- A. P=V/I
- B. P=VI
- C. 2P=l+V
- D. All of them
Explanation: Electric power is the rate at which work is done or energy is transformed into an electrical circuit. P=W/t P= QV/t *I = Q/t P= IV
Correct answer: P=VI- A. Metallic conductors at low temperature
- B. Metallic conductors at high temperature
- C. For electrolytes, when current passes through them
- D. For diode when current flows
Explanation: FACT. Ohm's law is only true for metallic conductors at low temperatures.Ohm's law states that the current flowing through a conductor is…
Correct answer: Metallic conductors at low temperature- A. Zero
- B. Negative
- C. Positive
- D. About 2 ohms per degree
Explanation: For conductors ( like filament ) the temperature coefficient is Positive i.e as the temperature increases collision between electrons and…
Correct answer: Positive- A. Semiconductors
- B. D.C. circuits
- C. Small resistors
- D. High currents
Explanation: All AC Circuits and Conductors obey Ohm's Law as the current flowing through them is directly proportional to applied voltage i.e a…
Correct answer: Semiconductors- A. Increases
- B. Decreases
- C. Remains same
- D. None of the above
Explanation: This option suggests that as the applied voltage increases, the resistance of the carbon filament lamp also increases.
Correct answer: Increases- A. Temperature should remain constant
- B. Current should be proportional to voltage
- C. Resistance must be wire wound type
- D. All of the above
Explanation: Necessary condition for validity of Ohm's law is that physical condition such as temperature of the conductor remains same.
Correct answer: Temperature should remain constant- A. Aluminium
- B. Paper
- C. Rubber
- D. Mica
Explanation: In case of metals when we increase the temperature, the relative movement of the atoms as well the free electrons increase.
Correct answer: Aluminium- A. 150V
- B. 250V
- C. 50V
- D. 15V
Explanation: Option B is correct. V=IR50 X 5= 250 Voltage.
Correct answer: 250V- A. 0.3
- B. 0.6
- C. 0.5
- D. 0.75
Explanation: Figure 1 describes the first cell and figure 2 describes the second cell, both carrying the same current i.
Correct answer: 0.3- A. Series
- B. Parallel
- C. Both of them
- D. None of them
Explanation: Req = R1 † R2 † R3 † ......† Rn for series B. for parallel Req = 1/R1 † 1/R2 †.....† 1/Rn
Correct answer: Series- A. A column of mercury
- B. A cube of carbon
- C. A cube of copper
- D. The unit length of wire
Explanation: It is a fact that column of mercury is used to define ohm in terms of resistance.
Correct answer: A column of mercury- A. Power
- B. Energy
- C. Current
- D. Resistance
Explanation: Option B is correct as energy=power×time. SI unit of power is the watt (W) thus the kWh is a unit for "energy".
Correct answer: Energy- A. 12 ohm
- B. 120 ohm
- C. 120K ohm
- D. 120M ohm
Explanation: Human resistance is about 10,000 ohms on the high side and as little as 1,000 ohms if the person is wet.The Human body has different…
Correct answer: 120K ohm- A. Resistance must be uniform
- B. Current should be proportional to the size of the resistance
- C. Resistance must be wire wound type
- D. Temperature at the positive end should be more than the temperature at negative end
Explanation: Ohm's law states that the voltage or potential difference between two points is directly proportional to the current or electricity…
Correct answer: Resistance must be uniform- A. Almost zero
- B. Almost infinite
- C. No prediction at all
- D. May increase or decrease
Explanation: The resistance of a conductor at absolute zero (0K) is almost zero. This phenomenon is known as zero or near-zero resistance, and it…
Correct answer: Almost zero- A. Series
- B. Parallel
- C. Both of them
- D. None of them
Explanation: When resistors are connected in parallel, the potential difference across all the resistors is the same. The total current is given by,
Correct answer: Parallel- A. Volts
- B. Couloumb
- C. Metre
- D. Newton's
Explanation: Option A is correct since the correct unit of potential difference in volts.Option B is incorrect since coulombs is the SI unit of…
Correct answer: Volts- A. 160 Ohms
- B. 80 Ohms
- C. 20 Ohms
- D. 10 Ohms
Explanation: The resistance of the conductor is given by: R = ρ/AAs the area of cross section increases, resistance decreases.Resistance of thin wire =…
Correct answer: 10 Ohms- A. Infinite
- B. zero
- C. minimum
- D. maximum
Explanation: Option A is correct since, in a short circuit, there is no resistance to the flow of charges so a large number of charges flow in a very…
Correct answer: Infinite