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 52 of 53
- A. Resistance
- B. Conductance
- C. Temperature coefficient of resistivity
- D. Conductivity
Explanation: When two metals have the same resistance, they can be differentiated based on their conductivity.
Correct answer: Conductivity- A. the same
- B. one fourth
- C. double
- D. one half
Explanation: Resistivity remains constant, it is a constant value.
Correct answer: the same- A. 3R
- B. R/3
- C. R
- D. 2R
Explanation: When three equivalent resistors are connected in parallel, the equivalent resistance is 3/R.
Correct answer: 3R- A. Semiconductors
- B. Tungsten filament
- C. Thermistor
- D. Metals
Explanation: Ohmic materials are those that follow Ohm's Law, where the resistance (R) is constant regardless of the applied voltage (V) or current…
Correct answer: Metals- A. 2R
- B. 4R
- C. 8R
- D. 16R
Explanation: To determine the new resistance, use the formula Resistance = resistivity × length/area.
Correct answer: 8R- A. Copper
- B. Thermistor
- C. Soft iron
- D. Platinum
Explanation: NTC, negative thermistors are resistors with a negative temperature coefficient which means the resistance decreases with increasing…
Correct answer: Thermistor- A. 50 W
- B. 750 W
- C. 500 W
- D. 1000 W
Explanation: To find the power dissipated in the cables, you need to first calculate the current flowing through the circuit.
Correct answer: 500 W- A. Thermistor
- B. Bulb filament
- C. Metals
- D. Semiconductors
Explanation: Ohm's law is valid for metallic conductors because they have a linear relationship between current and voltage.
Correct answer: Metals- A. Increase
- B. Decrease
- C. Not change
- D. None of these
Explanation: In a parallel circuit, the net resistance decreases as more components are added, because there are more paths for the current to pass…
Correct answer: Decrease- A. 2.5 times
- B. 5 times
- C. 10 times
- D. 30 times
Explanation: The Resistance of a wire is calculated asR = P L/Awhere R = resitance of the wireL = Length of the wireA is the area of the wire = (pi…
Correct answer: 2.5 times- A. 0.25 A
- B. 1.0 A
- C. 4.0 A
- D. 5.0 A
Explanation: Parallel Resistance is calculated by 1/Rt= (1/R1 + 1/R2 ...) hence Rt = 5Ohm. EMF is 20, and Ohm's Law, V=IR, determines I (current) as 4.0A
Correct answer: 4.0 A- A. Only the current is doubled
- B. Only the current is halved
- C. Only the resistance is doubled
- D. Only the resistance is halved
Explanation: The correct answer is that only the current is doubled. According to Ohm's law (V = IR), the current through a resistor is directly…
Correct answer: Only the current is doubled- A. r/2
- B. 4r
- C. 2r
- D. r/4
Explanation: When a wire is stretched to double its length, its resistance R changes according to the formula: [R' = 2R] So, the resistance of the wire…
Correct answer: 4r1034. What is the current in a 2 x 10^6 ohms resistor having a potential difference of 6 x 10^-3 volts?
- A. 1 x 10^-3 A
- B. 2 x 10^-3 A
- C. 3 x 10^-3 A
- D. 4 x 10^-3 A
Explanation: We know according to ohm's law.V=IRI = V/RPutting valuesWe get answer3×10-3 A
Correct answer: 3 x 10^-3 A1035. What is the current in a 2 x 10^6 ohms resistor having a potential difference of 6 x 10^3 volts?
- A. 1 x 10^-3 A
- B. 2 x 10^-3 A
- C. 3 x 10^-3 A
- D. 4 x 10^-3
Explanation: According to Ohm's Law V=IR Since V= 6x103 Volts R= 2 x 106 ohms Hence; I=V/R; I = 6x103 / 2x106 = 3x10-3 Ampere (so option C is the…
Correct answer: 3 x 10^-3 A- A. One ampere
- B. Two ampere
- C. 1.6x 10+19 amperes
- D. 1.6 x 10^-19 amperes
Explanation: I = Q/t = Ne/t = 2 x 1.6 x 10-19 / 2 = 1.6 x 10-19 A. Therefore, D is the correct answer.
Correct answer: 1.6 x 10^-19 amperes- A. Kirchholf's 1st law
- B. Wheatstone bridge
- C. Combination of resistance
- D. Kirchholf's 2nd law
Explanation: Wheatstone Bridge: The Wheatstone bridge is a circuit arrangement consisting of four resistive elements connected in a diamond shape.
Correct answer: Wheatstone bridge- A. Current
- B. Time
- C. Quantity of charge
- D. Power
Explanation: Quantity of charge: This option is correct. Ampere hour is a unit of the quantity of charge, representing the total charge transported by…
Correct answer: Quantity of charge- A. Same current
- B. Same power
- C. Different potential and same current
- D. Same potential difference
Explanation: In a parallel circuit, each appliance is connected directly to the main line and the neutral line, creating individual pathways for the…
Correct answer: Same potential difference- A. voltage of battery
- B. power of battery
- C. e.m.f of battery
- D. all of these
Explanation: EMF is the source of voltage in a battery responsible for flow of charges through a circuit.
Correct answer: e.m.f of battery