SSC CGL Science – Electricity & Magnetism – Level 3 · Challenge

← Back

SSC CGL Science – Electricity & Magnetism – Level 3 · Challenge – 8 questions, subject: General Science. Every question has the correct answer with a one-line explanation; tap "Show Answer". Free practice for TNPSC, UPSC, SSC, Bank and RRB exams – Shanmugam IAS Academy, Coimbatore.

Get daily current affairs & exam alerts – follow us YouTube WhatsApp Channel Telegram Channel Facebook Page Instagram
Share with friends & study groups
Link to this page from your website / blog (HTML code)
1.  
Three resistors of 6 Ω each can be combined to give all of these EXCEPT:

Correct Answer: C [12 Ω]

Explanation:

Series 18, parallel 2, 6 + (6∥6) = 9, (6 + 6)∥6 = 4; 12 Ω is not possible with all three.

2.  
A wire of resistance 8 Ω is stretched to twice its length. Its new resistance is:

Correct Answer: D [32 Ω]

Explanation:

Answer: 32 Ω. n² = 4 → 32 Ω.

3.  
A 100 W bulb and a 25 W bulb (both rated 220 V) are joined in parallel across 220 V mains. Which glows brighter?

Correct Answer: A [the 100 W bulb]

Explanation:

In parallel each bulb gets its full 220 V and gives its rated power – 100 W > 25 W (in series it would be the other way).

4.  
Spot My Mistake“A heater rated 2000 W, 220 V can safely be used on a 5 A lighting circuit.” The correct statement is:

Correct Answer: C [It draws about 9.1 A, so it needs the 15 A power circuit]

Explanation:

Answer: It draws about 9.1 A, so it needs the 15 A power circuit. I = P/V = 2000/220 ≈ 9.1 A.

5.  
A current of 3 A produces 900 J of heat in a resistor in 10 s. If the current is reduced to 1 A, the heat in 10 s will be:

Correct Answer: D [100 J]

Explanation:

H ∝ I² → (1/3)² = 1/9 → 900/9 = 100 J.

6.  
A compass needle is placed below a wire carrying current from south to north. The north pole of the needle deflects towards the:

Correct Answer: B [west]

Explanation:

Below the wire the field (right-hand thumb rule) points west.

7.  
If the potential difference across a resistor is doubled, the power dissipated in it becomes:

Correct Answer: A [four times]

Explanation:

Answer: four times. P = V²/R.

8.  
Reverse questionThe answer is “short circuit”. Which situation does it describe?

Correct Answer: C [Live and neutral wires touch through damaged insulation]

Explanation:

Resistance almost zero → huge current.

➤ Full notes, shortcuts and every answer explained – SSC CGL 2026 General Science book (₹149): www.shanmugamiasacademy.in/study-materials/ssc-cgl-general-science

📘 SSC CGL 2026 – General Science (Tier I + Tier II)
Here you get the answer with a one-line explanation. 1,110 original questions with answer key and explanations · mind-maps, notes, tables and shortcuts · Tier I and Tier II practice sets + 3 mock tests
Get the book – ₹149 ₹299 →
Score: 0 Answered: 0 / 0