636: Assertion (A):
In the periodic table of chemical elements, electron affinity is always found to increase from top to bottom in a group.
Reason (R):
In a group, the atomic radial generally increase from top to bottom.
(a) Both A and R are individually true and R is the correct explanation of A
(b) Both A and R are individually true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
637: The ancient Indian coins were introduced during the:
(a) 3rd century AD
(b) 3rd century BC
(c) Kanishka's period
(d) Ashoka's reign
638: Match List I (Naturally occurring substances) with List II (Elements) and select the correct answer using the codes given below the Lists:
List I
I. Diamond
II. Marble
III. Sand
IV. Ruby
List II
(A) Calcium
(B) Silicon
(C) Aluminium
(D) Carbon
Codes:
(a) I-C, II-A, III-B, IV-D
(b) I-D, II-B, III-A, IV-C
(c) I-B, II-A, III-C, IV-D
(d) I-D, II-A, III-B, IV-C
639: Consider the following statements :
1. Kyoto Protocol came into force in the year 2005
2. Kyoto Protocol deals primarily with the depletion of the Ozone layer.
3. Methane as a greenhouse gas is more harmful than carbon dioxide
Which of the statements given above is/are correct?
(a) 1 Only
(b) 1 and 2
(c) 1 and 3
(d) 3 Only
640: Regarding "carbon credits", which one of the following statements is not correct?
(a) The goal of the carbon credit system is to limit the increase of carbon dioxide emission
(b) Carbon credits are awarded to countries or groups that have reduced greenhouse gases below their emission quota
(c) Carbon credits are traded at a price fixed from time to time by the United Nations Environment Programme
(d) The carbon credit system was ratified in conjunction with the Kyoto Protocol