Answer: A) Decrease in the thickness of ozone layer in Stratosphere Explanation:

Answer: D) 3 : 2 Explanation: Let the speeds of the two trains be x m/sec and y m/sec respectively. Then, length of the first train = 27 x meters, and length of the second train = 17 y meters. (27 x + 17 y) / (x + y) = 23 => 27 x + 17 y = 23 x + 23 y => 4 x = 6 y => x/y = 3/2.

Answer: A) Pascal's Law Explanation:

Answer: B) Proton Explanation: Protons carry a positive electrical charge, electrons carry a negative electrical charge and neutrons carry no electrical charge at all. The protons and neutrons cluster together in the central part of the atom, called the nucleus, and the electrons 'orbit' the nucleus.

Answer: C) Fe Explanation: In chemistry, the term transition metal has three possible meanings: The IUPAC definition defines a transition metal as "an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell". Any of the set of metallic elements occupying a central block (Groups IVB–VIII, IB, and IIB, or 4–12) in the periodic table, e.g. iron, manganese, chromium, and copper. Chemically they show variable valency and a strong tendency to form coordination compounds, and many of their compounds are coloured.   Here in the given options, only iron (Fe) is a transition metal since Strontium is an alkaline earth, arsenic is a metalloid, hydrogen is (normally) a diatomic gas.

Answer: B) 178 cm Explanation: Area of square = 40 x 40 = 1600 sq.cm Given that the areas of Square and Rectangle are equal => Area of rectangle = 1600 Sq.cm We know that, Area of rectangle = L x B Given L = 64 cm Breadth of rectangle = 1600/64 = 25 cm Perimeter of the rectangle = 2(L + B) = 2(64+25) = 178 cm.

Answer: A) Chandigarh Explanation:

Answer: D) 360 mts Explanation: Speed of the Train K is given by s = d/t = 240/20 = 12 m/sDistance covered by Train K in 50 seconds = 12 x 50 = 600 mts.But it crosses Train L in 50 seconds Therefore, the length of the Train L is = 600 - 240 = 360 mts.