COMEDK Mock Test - 3 - JEE MCQ

A wheel is subjected to uniform angular acceleration about its axis. Initially its angular velocity is zero. In the first 2 sec, it rotates through an angle q1; in the next 2 sec it rotates through an additional angle θ₂, the ratio θ₂/θ₁ is   

Half-life of a radioactive substance A is 4 days. The probability of a nucleus that, from the given sample that it will decay in two half-lives is

Two bulbs consume the same power when operated at 200 V and 300 V respectively. When these bulbs are connected in series across a DC source of 400 V, then the ratio of power consumed across them is

One main scale division of a vernier calliper is 'a' cm and n^th division of the vernier scale coincides with (n - 1)^th division of the main scale. The least count of the callipers in mm is:

When the temperature of a metal wire is increased from 0°C to 10°C, its length increases by 0.02%. The percentage change in its mass density will be closest to:

A body is projected up a smooth inclined plane with velocity v from the point A as shown in the figure. The angle of inclination is 45° and the top is connected to a well of diameter 40 m. If the body just manages to cross the well, what is the value of v? Length of the inclined plane is 20√2 m.

A fly wheel is accelerated uniformly from rest and rotates through 5 rad in the first second. The angle rotated by the fly wheel in the next second will be:

A projectile is fired at an angle 60° with some velocity u. If the angle is changed infinitesimally, let the corresponding fractional changes in the range and the time of flight be x and y, respectively, then find the value of y.

Which of the following electromagnetic waves have the longest wavelength?

A charge Q is moving distance in the magnetic field  Find the value of work done by 

A light of intensity I₀ is incident on a Polaroid which placed at 30º . Find the ratio of the intensity of light after and before polarization, if the light is polarized when Polaroid is at 60º.

A complex compound of Co²⁺ with molecular formula CoCl_xyNH₃ gives a total of three ions per molecule when dissolved in water. How many Cl⁻ ions satisfy primary as well secondary valencies in this complex?

The amount of electricity that can deposit 108 g of silver from silver nitrate solution is

Among the following oxides, the least acidic is

Which of the following statements is correct regarding ease of dehydration?

An aldehyde on oxidation gives

A liquid is in equilibrium with its vapour at its boiling point. The molecules in these two phases will have equal

Nickel is purified by thermal decomposition of its

Given below are the oxides:
Na₂O, As₂O₃, N₂O, NO and Cl₂O₇
The number of amphoteric oxides is:

Consider A, B, C and D with position vectors 7î - 4ĵ + 7k̂, î - 6ĵ + 10k̂, -î -3ĵ + 4k̂ and 5î - ĵ + 5k̂ respectively. Then ABCD is a

If x = 1998!, then value of the expression

How many different nine-digit numbers can be formed from the number 2, 2, 3, 3, 5, 5, 8, 8, 8 by rearranging its digit so that the odd digits occupy even positions?

 then x is equal to

A random variable X has the following probability distribution:

The mean and standard deviations, respectively, are

If the system of equations x + ay + az = 0, bx + y + bz = 0 and cx + cy + z = 0, where a, b and c are non-zero and non-unity, has a non-trivial solution, then the value of  is

The triangle formed by the tangent to the curve f(x) = x² + bx - b at the point (1, 1) and the co-ordinate axis, lies in the first quadrant. If its area is 2, then the value of b is

If w³ = 1 and w ≠ 1, then (1 + w)(1 + w²)(1 + w⁴)(1 + w⁸) =