NEET (UG)

Practice Test 1 — Current Electricity

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct)

Question 1

The SI unit of electric current is the:

Solution: Current is measured in amperes.

Question 2

The resistance of a wire of length $L$ and area $A$ is:

Solution: $R = \rho L/A$.

Question 3

Three $3\ \Omega$ resistors in parallel give:

Solution: $1/R_p = 3/3 = 1 \Rightarrow R_p = 1\ \Omega$.

Question 4

The terminal voltage of a cell of EMF $\varepsilon$ delivering current $I$ through internal resistance $r$ is:

Solution: $V = \varepsilon - Ir$.

Question 5

Kirchhoff's loop rule expresses conservation of:

Solution: KVL is energy conservation.

Question 6

Heat produced in a resistor in time $t$ is:

Solution: Joule's law: $H = I^2 R t$.

Question 7

A galvanometer becomes a voltmeter when connected with a:

Solution: High resistance in series makes a voltmeter.

Question 8

A balanced Wheatstone bridge has galvanometer current equal to:

Solution: At balance, no current flows through the galvanometer.

Section B — Assertion & Reason

Question 9

A: A 100 W bulb has a lower resistance than a 60 W bulb of the same voltage rating.
R: At a fixed voltage, power dissipated is inversely proportional to resistance.

Solution: $P = V^2/R$, so higher power means lower resistance — R explains A.

Question 10

A: An ammeter is connected in series in a circuit.
R: An ideal ammeter has zero resistance so it does not change the current it measures.

Solution: Both statements are true, but the reason for series connection (to measure the same current) is not the same as having zero resistance — R does not directly explain A.

Question 11

A: A potentiometer can measure EMF more accurately than a voltmeter.
R: At the balance point a potentiometer draws no current from the cell.

Solution: Drawing no current avoids the loading error, so the potentiometer is more accurate — R explains A.

Question 12

A: The drift velocity of electrons in a conductor is very high, of the order of the speed of light.
R: Electric current is established almost instantly when a circuit is switched on.

Solution: Drift velocity is very small (A is false); the field, not the electrons, propagates near light speed, so current starts almost instantly (R is true).