Coefficient of variation of two distributions are 60 and 70,and their standard deviations are 21 and 16, respectively.Their arithmetic means are?

the radius of curvature of a thin plano-convex lens is 10 cm(of curved surface) and the refractive index is 1.5. If the plane surface is silvered, then it behaves like a concave mirror of focal length?

A body initially at 80°C cools to 64°C in 5 minutes and to52°C in 10 minutes. The temperature of the body after 15minutes will be ?

What is Simple Harmonic Motion? Explain?

A school has four sections of chemistry in class XII having40, 35, 45 and 42 students. The mean marks obtained inChemistry test are 50, 60, 55 and 45 respectively for the four sections, the over all average of marks per students is?

t very high temperatures vibrational degrees also becomes active. At such temperatures an ideal diatomic gas has a molar specific heat at constant pressure, Cp is?

The radius of curvature of a thin plano-convex lens is 10 cm(of curved surface) and the refractive index is 1.5. If theplane surface is silvered, then it behaves like a concavemirror of focal length?

A ball is thrown upward with initial velocity v0 = 15.0 m/s atan angle of 30° with the horizontal. The thrower stands nearthe top of a long hill which slopes downward at an angle of20°. When does the ball strike the slope ?

Dimensionally wavelength is equivalent to?

A small mass slides down a fixed inclined plane of inclination with the horizontal.

Let f (x) be a polynomial function of second degree. If f (1) = f (–1) and a, b, c are in A.P., then f'(a),

f'(b) and f'(c) are in?

In a geometric progression consisting of positive terms, each term equals the sum of the next two terms. Then the common ratio of this progression is equals

The first two terms of a geometric progression add up to 12. The sum of the third and the fourth terms is 48. If the terms of the geometric progression are alternately positive and negative, then the first term is?

A student is to answer 10 out of 13 questions in an examination such that he must choose at least 4 from the first five questions. The number of choices available to him is?

The reason for double helical structure of DNA is operation of?

Why RNA is different from DNA?

Which of the following liquid pairs shows a positive deviation from Raoult’s law?

(a) Water hydrochloric acid

(b) Benzene methanol

(c) Water nitric acid

(d) Acetone chloroform.

Based on lattice energy and other considerations which one of the following alkali metal chlorides is expected to have the highest melting point?

(a) LiCl

(b) NaCl

(c) KCl

(d) RbCl

According to the periodic law of elements, the variation in properties of elements is related to their?

Lattice energy of an ionic compound depends upon?

A mass m hangs with the help of a string wrapped around a pulley on a frictionless bearing. The pulley has mass m and radius R. Assuming pulley to be a perfect uniform circular disc, the acceleration of the mass m, if the string does not slip on the pulley, is?

A diatomic ideal gas is used in a Carnot engine as the working substance. If during the adiabatic expansion part of the cycle the volume of the gas increases from V to 32V, the efficiency of the engine is?

if gamma ray emission from a nucleus then what will be the number of nutron and proton?

The intensity of gamma radiation from a given source is I. On passing through 36 mm of lead, it is reduced to I/8. The thickness of lead which will reduce the intensity to I/2 will be?

A radioactive sample at any instant has its disintegration rate 5000 disintegrations per minute.After 5 minutes, the rate is 1250 disintegrations per minute. Then, the decay constant (per minute) is?

If N0 is the original mass of the substance of half life period t1/2 = 5 years, then the amount of substance left after 15 years is?

What is Human excretory system? explain?

A car, starting from rest, accelerates at the rate f through a distance s, then continues at constant speed for time t and then decelerates at the rate f/2 to come to rest. If the total distance traversed

is 15 s, then what will be the value of s?

Two particles, 1 and 2, move with constant velocities v1 and v2. At the initial moment their radius vectors are equal to r1 and r2.How must these four vectors be interrelated for the particles to collide?

Consider a car moving on a straight road with a speed of 100 m/s. The distance at which car can be stopped is?

A light string passing over a smooth light pulley connects two blocks of masses m1 and m2 (vertically). If the acceleration of the system is g/8, then the ratio of the masses is?

The minimum velocity (in m/s ) with which a car driver must traverse a flat curve of radius150 m and coefficient of friction 0.6 to avoid skidding is?

A lift is moving down with acceleration a. A man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively?