Answer: C) Operating system Explanation: In a brief, the system software is the interface between the hardware and user applications. System software is a type of computer program that is designed to run a computer’s hardware and application programs.   Examples : OS, System utilities, BIOS like mouse, keyboard, hard disc, Device drivers, Assembler,...

Answer: B) largest railway station Explanation: Grand Central Terminal also referred to as Grand Central Station or Grand Central is the world’s largest railway station in terms of platforms in New York City with 44 platforms covering 48 acres.

Answer: C) Zn Explanation: In chemistry, a metal is an element that readily forms positive ions (cations) and has metallic bonds. Metals are opaque, lustrous elements that are good conductors of heat and electricity. Most metals are malleable and ductile and are, in general, denser than the other elemental substances.   Examples of metals are aluminium, copper, iron, tin, gold, lead, silver, titanium, uranium, and zinc.   Here Se - Selenium is an element but is not a metal, S - Sulphur is not a metal and I - Iodine is also not a metal.   Hence, Zn - Zinc is the only metal in the given options.

Answer: A) Total internal reflection Explanation: A periscope is an optical instrument that uses a system of prisms, lenses, or mirrors to reflect images through a tube.       Light from a distant object strikes the top mirror and is then reflected at an angle of 90 degrees down the periscope tube. At the bottom of the periscope, the light strikes another mirror and is then reflected into the viewer’s eye.   Hence, A periscope works by the principle of Total internal reflection.

Answer: A) as the price increases, the quantity demanded will decrease. Explanation:

Answer: C) 41 Explanation: The Super Bowl is the annual championship game of the National Football League (NFL). In Super bowl 2018, the Eagles secured a 41-33 victory, and the celebration of the franchise's first Super Bowl victory was on.

Answer: D) Inner core Explanation: "Pressure" is the ratio of mass to area. So, for any given area, the one with more mass pressing on it will experience a higher pressure.   As you go more deeply into the atmosphere OR earth itself, you are putting more and more mass over you. For the same unit area therefore, the pressure, (mass/area) increases.   Hence, the lowest layer will always have the highest pressure i.e, inner core.

Answer: A) Rs. 1600 Explanation: Let the salaries of Maneela and Shanthi one year before be M1, S1 & now be M2, S2 respectively. Then, from the given data, M1/S1 = 3/4  .....(1) M1/M2 = 4/5 .....(2) S1/S2 = 2/3  .....(3) and M2 + S2 = 4160  .....(4)   Solving all these eqtns, we get M2 = Rs. 1600.