476: Total internal reflection occurs when light travels from:
(a) A rarer medium to a denser medium
(b) A denser medium to a rarer medium
(c) A rarer medium to a denser medium and the angle of incidence is less than the critical angle
(d) A rarer medium to a denser medium and the angle of incidence is greater than the critical angle
477: On multiplying a number by 3, the product is a number each of whose digits is 7. What is the smallest such number?
478: Department of Border Management is a Department of which one of the following Union Ministries?
(a) Ministry of Home Affairs
(b) Ministry of Defence
(c) Ministry of Shipping, Road Transport and Highways
(d) Ministry of Environment and Forests
479: Match List I with List II and select the correct answer using the codes given below the lists :
List I---------------------List II
I. Deccan Traps-------(A) Late Cenozoic
II. Western Ghats----(B) Pre-Cambrian
III. Aravalli-------------(C) Cretaceous-Eocene
IV. Narmada-Tapi-----(D) Cambrian Alluvial deposits
-------(E) Pleistocene
Codes:
(a) I-C, II-E, III-A, IV-D
(b) I-C, II-A, III-B, IV-E
(c) I-B, II-A, III-C, IV-D
(d) I-A, II-D, III-B, IV-E
480: Consider the following statements :
1. Caffeine, a constituent of tea and coffee is a diuretic.
2. Citric acid is used in soft drinks.
3. Ascorbic acid is essential for the formation of bones and teeth.
4. Citric acid is a good substitution for ascorbic acid in our nutrition.
Which of the statements given above are correct ?
(a) 1 and 2, only
(b) 1, 2 and 3, only
(c) 3 and 4 only
(d) 1, 2, 3 and 4