SSC CGL Science – Modern Physics, Electronics & Everyday Devices – Level 1 · Warm-up · Tier I Level

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SSC CGL Science – Modern Physics, Electronics & Everyday Devices – Level 1 · Warm-up · Tier I Level – 12 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.

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1.  
A small packet (quantum) of light energy is called a:

Correct Answer: D [photon]

Explanation:

Light energy comes in quanta called photons, E = hf.

2.  
The Raman effect, for which C. V. Raman received the 1930 Nobel Prize in Physics, is about:

Correct Answer: A [the scattering of light by molecules]

Explanation:

Raman (1928): scattered light contains new wavelengths – the Raman effect.

3.  
Natural radioactivity was discovered in 1896 by:

Correct Answer: B [Henri Becquerel]

Explanation:

Becquerel – 1896 (uranium salts); Röntgen – 1895 (X-rays); Thomson – 1897 (electron).

4.  
Which of these radiations carries no electric charge?

Correct Answer: C [Gamma rays]

Explanation:

Gamma rays are photons (charge 0); α is +2, β⁻ and cathode rays are electrons (−1).

5.  
An alpha particle is identical to the nucleus of:

Correct Answer: C [helium]

Explanation:

α = 2 protons + 2 neutrons = helium nucleus.

6.  
Which of the following is a semiconductor?

Correct Answer: B [Germanium]

Explanation:

Germanium and silicon are semiconductors; copper conducts; glass and mica insulate.

7.  
The SI unit of radioactivity (activity) is the:

Correct Answer: A [becquerel]

Explanation:

1 becquerel = 1 decay per second; the curie is an older non-SI unit; gray measures absorbed dose.

8.  
A TV remote control sends signals using:

Correct Answer: D [infrared rays]

Explanation:

Answer: infrared rays. Remote controls use infrared.

9.  
Diagram-basedIdentify the logic gate shown:

Correct Answer: B [NOR gate]

Explanation:

Curved OR body + bubble at the output = NOR (output 1 only for inputs 0, 0).

10.  
The energy of the Sun comes mainly from:

Correct Answer: A [nuclear fusion of hydrogen into helium]

Explanation:

Stars shine by fusion: hydrogen nuclei join to form helium.

11.  
Fill in the blankA radioactive sample has a half-life of 4 days. After 12 days, ___ of it remains.

Correct Answer: C [1/8]

Explanation:

12 ÷ 4 = 3 half-lives → (1/2)³ = 1/8.

12.  
Statement-basedWhich is/are correct?
I. A junction diode conducts when forward biased.
II. An LED gives light when reverse biased.

Correct Answer: D [Only I]

Explanation:

A diode conducts in forward bias; an LED also glows only in forward bias, so II is false.

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

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