Answer: A) a wave reflects upon itself Explanation: A standing wave also known as a stationary wave, is a wave in which its peaks or any other point on the wave do not move spatially. This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling in opposite directions. The most common cause of standing waves is the phenomenon of resonance, in which standing waves occur inside a resonator due to interference between waves reflected back and forth at the resonator's resonant frequency.   Hence, standing wave occurs when a wave reflects upon itself.

Charles Babbage, the father of computer, invented the first general-purpose computer in an effort to prevent the mathematical errors that were prevalent in the human-calculated mathematics of his time.

Answer: A) Air Explanation: Light travels fastest in Vacuum. The fastest thing in the whole universe is the speed of light in a vacuum like outer space. It is about 2.99 x 108 m/s.

Answer: A) Aurora australis Explanation: Polar lights (aurora polaris) are a natural phenomenon found in both the northern and southern hemispheres that can be truly awe inspiring. Northern lights are also called by their scientific name, aurora borealis, and Southern lights are called aurora australis.

Answer: A) 1, 5 – hexadiene Explanation: 3 – Hexanol: There is no alcohol stretch present in the spectrum. Therefore, the above structure is not suitable for the given spectrum.   Trans – 4 – octene: There is no vinyl bending present in the spectrum. Therefore, the above structure is not suitable for the given spectrum. 1, 5 – hexadiene: The vinyl bending and other stretches were matched with the above structure.     Hence, the c = c stretch, vinyl bending and stretch were matched with the above structure. Therefore, the given spectrum belongs to 1, 5 – hexadiene.

Answer: B) Rs. 6540 Explanation: Given C.I = 5984, R = 20% , T = 2yrs  C.I = P1+201002-1   5984 =    => P = (5995x25)/11   P = Rs. 13625   Now S.I = PTR/100   SI = (13625 x 8 x 6)/100 = Rs. 6540

Answer: D) 6 Explanation: Sum of decimal places = 7. Since the last digit to the extreme right will be zero (since 4 x 5 = 20), so there will be 6 significant digits to the right of the decimal point.

Answer: B) Rs. 480 Explanation: Let the sum be Rs. P. Then,   P1+252x1002-P= 510   P[982- 1] = 510.   Sum = Rs. 1920   So, S.I. = (1920 x 25 x 2) / (2 x 100) = Rs. 480