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 35 of 53
- A. Area of cross section
- B. length
- C. Resistivity
- D. Temperature
Explanation: The resistance of a wire does inversely with the area of cross-sectional ,according to the formula: R = ρ * (L/A), where R is resistance…
Correct answer: Area of cross section- A. Internal battery
- B. Wet cell
- C. Voltmeter
- D. Ammeter
Explanation: The correct statement is A. Internal battery. A portable digital multimeter's ohmmeter function usually requires an internal battery to…
Correct answer: Internal battery- A. It will be doubled
- B. It will be one fourth
- C. It will be halved
- D. It will remain the same
Explanation: The correct statement is D. It will remain the same. The resistivity of each part of the wire will remain the same after cutting.
Correct answer: It will remain the same- A. 1 Ω
- B. 2 Ω
- C. 20 Ω
- D. 10 Ω
Explanation: The correct answer is 2 Ω. This is determined by applying the formula for resistance, which is the inverse of conductance.
Correct answer: 2 Ω- A. 𝛒/2
- B. 𝛒
- C. 2𝛒
- D. 𝛒/3
Explanation: When a wire is cut into two equal halves, the resistivity (𝛒) of the material from which the wire is made remains unchanged.
Correct answer: 𝛒- A. Thick, short and cool
- B. Thin, long and hot
- C. Thick, long and hot
- D. Thin, short and cool
Explanation: The correct answer is Thick, short and cool because resistance is inversely related to the cross-sectional area and directly related to…
Correct answer: Thick, short and cool- A. 100 volts
- B. 110 volts
- C. 120 volts
- D. 0.002 volts
Explanation: The voltage drop across the resistor can be calculated using Ohm's Law:V = I × Rwhere:V = voltage drop (in volts)I = current (in amperes)R…
Correct answer: 100 volts688. Ohm's law states that the current is directly proportional to _ and inversely proportional to _
- A. resistance, current
- B. resistance, voltage
- C. voltage, current
- D. voltage, resistance
Explanation: Ohm's law states that the current (I) flowing through a conductor is directly proportional to the voltage (V) applied across it, and…
Correct answer: voltage, resistance- A. Voltage regulator
- B. Circuit Breaker
- C. Capacitor
- D. Transformer
Explanation: A voltage regulator is an electronic device that is used to regulate and stabilize the voltage levels in an electrical circuit.
Correct answer: Voltage regulator- A. Instantaneous current, instantaneous voltage
- B. Instantaneous power, instantaneous voltage
- C. instantaneous voltage, instantaneous conductance
- D. Instantaneous current, instantaneous power
Explanation: The instantaneous power (P) supplied to a circuit is the product of the instantaneous current (I) and instantaneous voltage (V):P = V x…
Correct answer: Instantaneous current, instantaneous voltage- A. The nature of the conductor
- B. Dimension of the conductor
- C. Physical state of the conductor
- D. All
Explanation: The resistance of a conducting material depends on several factors, including:a.
Correct answer: All- A. Germanium and silicon
- B. Germanium and iron
- C. Iron and silicon
- D. Iron and copper
Explanation: Germanium and silicon, which are semiconductors, exhibit a negative temperature coefficient of resistance.
Correct answer: Germanium and silicon- A. Electric charge: Ampere (A)
- B. Current: Volt (V)
- C. Electric power: Watt (W)
- D. Resistance: coulomb
Explanation: Electric power: Watt (W), which is correct. Watt is the unit of electric power, defined as the rate of energy transfer.
Correct answer: Electric power: Watt (W)- A. 100 watt
- B. 200 watt
- C. 300 watt
- D. 400 watt
Explanation: In this question, we are asked to determine which bulb has the least resistance when the current is kept constant.
Correct answer: 400 watt695. How much energy is converted in a resistor of 5 ohm carrying a current of 2.0 A after 10 seconds?
- A. 4.0 J
- B. 25 J
- C. 100 J
- D. 200 J
Explanation: Explanation:The energy (E) dissipated in a resistor is given by the formula: E = I²Rt, where I is the current, R is the resistance, and t…
Correct answer: 200 J- A. Ohm−1m
- B. mho m−1
- C. siemen m
- D. mho−1m−2
Explanation: Explanation:Conductivity (σ) is the reciprocal of resistivity (ρ). Resistivity has units of ohm-meter (Ω⋅m).Therefore, conductivity has…
Correct answer: mho m−1- A. 50 W
- B. 41 W
- C. 53 W
- D. 62 W
Explanation: Explanation:Total resistance (R) = internal resistance (r) + heater resistance (R_heater) = 1.5 Ω + 6.5 Ω = 8 Ω.
Correct answer: 41 W- A. It measures the emf of a cell very accurately
- B. Its sensitivity is low
- C. It is based on the null deflection method
- D. Its sensitivity is high
Explanation: Incorrect. This statement is not correct because potentiometers are highly sensitive due to their null deflection method, which avoids…
Correct answer: Its sensitivity is low- A. Both emf and terminal potential difference gradually changes
- B. Both emf and terminal potential difference changes
- C. Its emf changed but terminal potential difference remains same
- D. Both emf and terminal potential difference remains same
- E. Its emf remains same but terminal potential difference changes
Explanation: When different resistors are connected across terminals of battery their emf remains same but terminal potential difference changes.
Correct answer: Its emf remains same but terminal potential difference changes- A. V1=E+Ir
- B. V1 =E-Ir
- C. V1 =E/1-r
- D. V1 = Er
- E. V1 =E/I+r
Explanation: The terminal potential (V1) of a battery with an internal resistance (r) when a current (I) is drawn can be calculated using the formula…
Correct answer: V1 =E-Ir