Q. When vapors of a substance are cooled and changes into liquid, it is called
(A) conduction
(B) condensation
(C) convection
(D) evaporation
The answer is: (B) condensation ☑
Q. An instrument used to measure gas pressure is called
(A) ammeter
(B) barometer
(C) galvanometer
(D) manometer
The answer is: (D) manometer ☑
Q. If we add salt to the pure water, its boiling point will
(A) increase
(B) decrease
(C) remain same
(D) none of these
The answer is: (A) increase ☑
Q. The boiling point of alcohol is
(A) 71 °C
(B) 75 °C
(C) 79 °C
(D) 83 °C
The answer is: (C) 79 °C ☑
Q. The presence of impurities __________ the freezing point of water.
(A) increases
(B) decreases
(C) accelerate
(D) do not have any effect on
The answer is: (B) decreases ☑