Physics: Modern Physics: UPSC Previous Year Questions (Science and Technology)
2 previous year UPSC Prelims questions on Physics: Modern Physics (Science and Technology). Choose an option to see the answer and explanation.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 1–2 of 2 questions
UPSC 2000Science and Technology · Physics: Modern Physics
Q1. For reproducing sound, a CD (Compact Disc) audio player uses a:
Explanation
Option (c) is correct: A CD (Compact Disc) audio player uses a laser beam to read the digital information encoded on the surface of the disc. The laser scans the tiny pits and lands that represent the audio data, and the player converts this data into an audio signal. Options (a), (b) and (d) are incorrect:
Quartz crystal: Used in electronic devices like oscillators and watches, but not for sound reproduction in a CD player. Titanium needle: Historically used in turntables or record players (vinyl), not in CD players. Barium titanate ceramic: Used in piezoelectric devices like speakers, but not in reading CDs.
UPSC 2000Science and Technology · Physics: Modern Physics
Q2. Which one of the following does a TV remote control unit use to operate a TV set?
Explanation
A TV remote control typically uses radio waves to communicate with the TV set. Radio waves are a form of electromagnetic radiation that enables the remote to send signals over short distances to control the television. Radio waves are widely used in radio and television broadcasting, enabling the transmission of audio and video signals over long distances. They are also essential in wireless communication systems, including mobile phones, Wi-Fi, and satellite communication. Note: In many sources, infrared waves are identified as the mechanism behind the functioning of TV remote controls, but this option is not provided in the given choices.
Additional insight:
Light waves: Light waves are used in technologies like fiber optics for high-speed internet and communication. Sound waves: Sound waves are used in audio devices, medical imaging (ultrasound), and sonar systems. Microwaves: Microwaves are used in radar, satellite communications, and cooking (microwave ovens).
Answer key for these questions
Q
UPSC year
Correct answer
1
2000
(c) laser beam
2
2000
(d) Radio waves
Frequently asked questions
How many previous year UPSC questions are there on Physics: Modern Physics?
This page covers 2 previous year UPSC Prelims GS Paper-I questions on Physics: Modern Physics (Science and Technology), asked from 1996 to 2007. Each has the correct answer and an explanation.
How should I use previous year UPSC questions for Prelims?
Attempt each question first, then open the answer and read the explanation for every option. Repeat by chapter, and track which statements UPSC reuses across years. Previous year questions show the exam pattern and difficulty level.
Which years are covered for Physics: Modern Physics?
Questions on Physics: Modern Physics (Science and Technology) are available for 6 years, from 1996 to 2007. Use the Year filter to practise a single paper.
