Free Physics in Daily Life MCQs with Answers

131. Mass spectrograph was Invented by?

• A. Rutherford
• B. Chadwik
• C. F.W.Aston
• D. None of these

Explanation: F. W. Aston invented the mass spectrograph and used it to identify isotopes and measure their masses. Rutherford and Chadwick made major nuclear discoveries but did not invent this instrument.

132. With the rise in temperature, metals conductivity____________?

• A. Remains same
• B. Increases
• C. Decreases
• D. None of these

Explanation: In metals, rising temperature increases lattice vibrations, which scatter moving electrons more strongly. Electrical conductivity therefore decreases, while resistance increases.

133. Speed of sound in water at 20 °C is___________?

• A. 1450 m/s
• B. 1474 m/s
• C. 1498 m/s
• D. 1500+ m/s

Explanation: The speed of sound in fresh water near 20 °C is approximately 1,480 m/s; many standard tables give about 1,474 to 1,482 m/s depending on the assumed water conditions. Thus 1,474 m/s is the intended closest listed value.

134. Max plank is famous for his discovery of?

• A. Energy quanta
• B. photon
• C. both of these
• D. None of these

Explanation: Max Planck introduced the idea that energy is emitted or absorbed in discrete packets called quanta. The photon was later proposed as the quantum of electromagnetic radiation, especially through Einstein’s work.

135. Unit of surface tension in cgs system is?

• A. Pascal
• B. N/m
• C. Dyn/cm
• D. None of these

Explanation: Surface tension has the dimensions of force per unit length, so its CGS unit is dyne per centimetre. Pascal and newton per metre are SI pressure and SI surface-tension units respectively.

136. Who gave the idea of law of inertia?

• A. Dalton
• B. Galileo Galilei
• C. Bacon
• D. Einstein

Explanation: Galileo developed the principle of inertia through his studies of motion and inclined planes. Newton later stated it formally as the first law of motion.

137. Which of the following is a positively charged particle emitted by a radioactive element?

• A. Beta Rays
• B. Alpha Rays
• C. Gamma Rays
• D. None of these

Explanation: Alpha radiation consists of positively charged helium nuclei, containing two protons and two neutrons. Beta and gamma radiation have different properties, with gamma rays carrying no charge.

138. The fastest bird is the Peregrine Falcon, clocked at speeds of up to _____ miles per hour?

• A. 240
• B. 250
• C. 260
• D. 230

Explanation: A peregrine falcon can reach about 240 miles per hour during its high-speed hunting dive, making it the fastest bird by diving speed.

139. Most gases conduct electricity at:

• A. Normal pressure
• B. Very low pressure
• C. Very high pressure
• D. None of these

Explanation: Most gases become better electrical conductors at very low pressure because energetic electrons can travel farther and ionise more gas molecules. At normal pressure, frequent collisions limit this process.

140. Refraction of sound can occur in:

• A. Water
• B. Air
• C. Both A & B
• D. None of these

Explanation: Sound changes direction when its speed varies between media or across layers of a medium, so refraction can occur in both air and water.