Answer: A) Glass Explanation: Because the refractive index of glass is highest, light travels slowly in Glass.  We know that the speed of light depends on the refraction index. The higher the index of refraction is, the slower the speed of light is. R.I of air and vacuum = 0 (air is a teeny bit more but can be taken as 0) R.I of water = 1.33 R.I of glass = 1.4.   Hence, Light travels slowest in Glass.

Answer: D) Can't be determined Explanation: We know that a negative value plus a positive value always count backward and the sign depends on the bigger value sign. When you are adding a negative number to a positive number, then the value counts backward and takes the sign of the biggest number.   For example:: Adding -5 and +2 -5 + 2 = -3 (big number is 5 and its sign is '-')   Adding -3 and  +5 +5 + (-3) = 5 - 3 = +2(big number is 5 and it has sign '+').

Answer: B) Darkness Explanation: The More You Have the Darkness, The Less You See i.e, visible less.

Answer: D) 8:3 Explanation: Let the man's rate upstream be x kmph and that downstream be y kmph. Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs. x x 8 4 = (y x 4) 5 44 x =4y 5  y = 11 x. 5  Required ratio = y + x : y - x 2 2    = 16x x 1 : 6x x 1 5 2 5 2    = 8 : 3 5 5    = 8 : 3.

Answer: B) 12 Explanation: Using BODMAS law, 3 x 3 + 3 - 3 + 3 = 3 x 3 = 12 = 12 + 3 - 3 + 3 =  9 + 3 = 12   Hence, 3 x 3 + 3 - 3 + 3 = 12.

Answer: C) 128 bits Explanation: IPv6 - Internet Protocol Version 6. IPv6 addresses have a size of 128 bits. Internet Protocol Version 6 [IPv6] is the successor to the Internet's first addressing infrastructure, Internet Protocol version 4 (IPv4). In contrast to IPv4, which defined an IP address as a 32-bit value, IPv6 address have a size of 128 bits.

Answer: A) HIV Explanation: ELISA - Enzyme-Linked Immuno Sorbent Assay.   An ELISA test may be used to diagnose: HIV, which causes AIDS.   An ELISA also called EIA, is a test that detects and measures antibodies in your blood. Antibodies are proteins that your body produces in response to harmful substances called antigens.

Answer: A) Savannah Explanation: Tropical grasslands, or savannas, are also the homes of primates in Africa and Asia; no savanna-living primates exist in South America. Tropical grasslands comprise a mixture of trees and grasses, the proportion of trees to grass varying directly with the rainfall.