alleryA potential difference of 12 V is applied across a resistor and a current of 3 A flows. What is its resistance?
A0.25 ohm
B36 ohm
C9 ohm
D4 ohm
Answer & Solution
Correct answer: D. 4 ohm
1. By Ohm's law, $R = \dfrac{V}{I}$.
2. Substitute $V = 12\,\text{V}$ and $I = 3\,\text{A}$.
3. $R = \dfrac{12}{3} = 4\,\Omega$.
4. Choosing 36 mistakenly multiplies $V\times I$ (that gives power, not resistance).
_Source: Samacheer Kalvi (TN SCERT) Class 10 Science, Unit 4 Electricity "Electricity", p.62_
Keep practising Effects of Electric Current
Browse all Effects of Electric Current questions for Tamil Nadu SSLC (Class 10), or explore more Science topics.
Related questions
Fill the Ohm's-law blanksWhat is the role of the earth (ground) wire in a domestic electric circuit?A wire of resistance R is cut into five equal parts. What is the resistance of each part?Two resistors give 2 ohm when joined in parallel and 9 ohm when joined in series. What areA wire of resistance 10 ohm is stretched uniformly until its length becomes three times thWhy does a bulb glow when the switch in a simple circuit is closed?A torch bulb is rated 3 V and draws a current of 600 mA. What electric power does it consuAn electric heater of power 1000 W is used for 3 hours every day. How much electrical ener