NEET Current Electricity — Set 12

Question 1

A $ 15 \, \Omega $ resistor dissipates $ 60 \, \text{W} $ of power. What is the voltage across it?

Accepted Answer

Power: $ P = \frac{V^2}{R} $. Rearrange: $ V = \sqrt{P R} $. Substitute: $ V = \sqrt{60 \times 15} = \sqrt{900} = 30 \, \text{V} $.

Question 2

In a Wheatstone bridge, what is the condition for no current to flow through the galvanometer?

Accepted Answer

No current flows when the bridge is balanced, i.e., $ R_1 / R_2 = R_3 / R_4 $, making the potentials at the galvanometer’s nodes equal, so the potential difference across it is zero.

Question 3

A circuit has a $ 8 \, \text{V} $ battery with $ 1 \, \Omega $ internal resistance and two resistors $ 3 \, \Omega $ and $ 6 \, \Omega $ in parallel. What is the total current?

Accepted Answer

Parallel resistance: $ \frac{1}{R_p} = \frac{1}{3} + \frac{1}{6} = \frac{2 + 1}{6} = \frac{3}{6} = 0.5 \Rightarrow R_p = 2 \, \Omega $. Total resistance: $ R_{\text{total}} = 1 + 2 = 3 \, \Omega $. Current: $ I = \frac{\varepsilon}{R_{\text{total}}} = \frac{8}{3} \approx 2.67 \, \text{A} $.

NEET Physics: Current Electricity — Practice Set 12

Q1. A \( 15 \, \Omega \) resistor dissipates \( 60 \, \text{W} \) of power. What is the voltage across it?

Q2. In a Wheatstone bridge, what is the condition for no current to flow through the galvanometer?

Q3. A circuit has a \( 8 \, \text{V} \) battery with \( 1 \, \Omega \) internal resistance and two resistors \( 3 \, \Omega \) and \( 6 \, \Omega \) in parallel. What is the total current?

Q4. A \( 24 \, \text{V} \) battery with negligible internal resistance is connected to a \( 4 \, \Omega \) and \( 8 \, \Omega \) resistor in series. What is the power dissipated in the \( 4 \, \Omega \) resistor?

Q5. What is the significance of the relaxation time in the context of electron drift in a conductor?

Q6. In a circuit with resistors, why does the total power dissipated equal the power supplied by the source in steady state?

Q7. In a circuit with a battery, why does the current establish almost instantaneously when the circuit is closed, despite the slow drift velocity of electrons?

Q8. A \( 7 \, \text{V} \) battery with \( 1 \, \Omega \) internal resistance is connected to a \( 6 \, \Omega \) resistor. What is the power dissipated in the internal resistance?

Q9. What is the primary source of energy dissipation in a resistor carrying current?

Q10. A \( 10 \, \text{V} \) battery with \( 2 \, \Omega \) internal resistance is connected to two resistors \( 4 \, \Omega \) and \( 6 \, \Omega \) in parallel. What is the current through the \( 6 \, \Omega \) resistor?