If the potential difference in a circuit is 240 V and the resistance is 60 Ω then the current flowing through the circuit is …………………….
A) 300 A
B) 180 A
C) 0.25 A
D) 4 A
1 Answers
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A resistance thermometer has resistance 95.2 Ω at the ice point and 138.6 Ω at the steam point. What resistance would be obtained
Here the thermometric property P is the resistance. If R is the resistance at 27 °C, Using equation, T = \(\frac{100(P_T-P_1)}{(P_T-P_1)}\) For T = 27 °C, P1 = 95.2 Ω, P2 = 138.6 Ω . ∴ 27 = \(\frac{100(R-95.2)}{(138.6-95.2)}\) ∴...
2 Answers 3 views
The net charge flowing through a crosssection of a conductor in unit time is …………………. when the conductor is in open circuit.
Correct option is D) zero
2 Answers 1 views
The potential difference between the ends of a conductor is directly proportional to the electric current passing through it at constant temperature.
A) Ohm’s law
2 Answers 1 views
Keeping the potential difference constant, the resistance of a circuit is doubled. The current will become
Correct option is B) half
2 Answers 1 views
Find the potential difference across a wire when the current passing through a wire is 0.8
Correct option is B) 8 V
2 Answers 1 views
Calculate the current flowing through a heater rated at 2 kW when connected to a 300 V d. c. supply.
Given: P = 2 kW = 2000 W, V = 300 V To find: Current (I) Formula: P = IV Calculation: From formula, I = \(\frac{P}{V}=\frac{2000}{300}\) = 6.67 A
2 Answers 1 views
A piece of platinum wire has resistance of 2.5 Ω at 0 °C. If its temperature coefficient of resistance is 4 × 10^-3/°C. Find the resistance
Given: R0 = 2.5 Ω α = 4 × 10-3/°C = 0.004/°C T = 80 °C To find: Resistance at 80 °C (RT) Formula: RT = R0(l + αT) Calculation: From formula, RT = 2.5 [1+ (0.004 × 80)] =...
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The drift velocity of free electrons in a conductor is vd, when the current is flowing in it. If both the radius and current are doubled
Correct option is: (C) \(\frac{v_d}{2}\)
2 Answers 2 views
When potential difference is applied across an electrolyte, then Ohm’s law is obeyed at (A) zero potential
Correct option is: (D) high potential.
2 Answers 1 views
If a battery of emf 2 V with internal resistance one ohm is connected to an external circuit of resistance R across it
Correct option is: (D) 3 Ω
2 Answers 1 views