3951: Protective action against harmful household insects and pests can be taken by the use of
(a) Infrasonic waves
(b) Microwaves
(c) Ultrasonic waves
(d) Low frequency radio waves
3952: Who of the following was/were economic critic/ critics of colonialism in India?
1. Dadabhai Naoroji
2. G. Subramania Iyer
3. R. C. Dutt
Select the correct answer using the code given below.
(a) 1 only
(b) 1 and 2 only
(c) 2 and 3 only
(d) 1, 2 and 3
3953: With reference to Indian satellites and their launchers, consider the following statements:
1. All the INSAT-series of satellites were launched abroad
2. PSLVs were used to launch IRS-series of satellites
3. India used the indigenously built cryogenic engines for the first time for powering the third stage of GSLV
4. GSAT, launched in the year 2001, has payloads to demonstrate digital broadcasts and internet services
Which of these statements are correct?
(a) 1, 2, 3 and 4
(b) 2, 3 and 4
(c) 1, 2 and 4
(d) 1 and 3
3954: If water contracts on freezing, which of the following would happen?
(a) Icebergs will completely float on the surface of water
(b) Ice would become more dense
(c) Lakes would freeze from top to bottom
(d) Rocks will crack due to freezing or internal water
3955: Assertion (A) :
Sodium metal is stored under kerosene.
Reason (R):
Metallic sodium melts when exposed to air.
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, but R is NOT a correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true