COMEDK Mock Test - 4 - JEE MCQ

A wall has two layers A and B ach made of different materials. Both layers have the same thickness. The thermal conductivity of the material of A is twice that of B. Under thermal equilibrium, the temperature difference across the wall is 36^∘C. The temperature difference across the layer A is:

A body rolls down an inclined plane without slipping. The kinetic energy of rotation is 50% of its translational kinetic energy. The body is:

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion: The electric flux of the electric field ∮ E.dA is zero. The electric field is zero everywhere on the surface.

Reason: The charge inside the surface is zero.

Amplitude modulated wave is represented by V_AM = 10[1 + 0.4cos(2π × 10⁴t)] cos(2π × 10⁷ t). The total bandwidth of the amplitude modulated wave is:

A deuteron and an alpha particle having equal kinetic energy enter perpendicular into a magnetic field. Let r_d and r_α  be their respective radii of circular path. The value of  is equal to

A cylinder of fixed capacity of 44.8 litres contains helium gas at standard temperature and pressure. The amount of heat needed to raise the temperature of gas in the cylinder by 20.0°C will be:
(Given: gas constant R = 8.3 JK^-1 mol^-1)

If , then the relative error in Z will be:

A cylindrical tank has a hole of diameter 2r in its bottom. The hole is covered wooden cylindrical block of diameter 4r, height h and density ρ/3.

Situation I : Initially, the tank is filled with water of density ρ to a height such that the height of water above the top of the block is h₁ (measured from the top of the block).

Situation II : The water is removed from the tank to a height h₂ (measured from the bottom of the block), as shown in the figure.
The height h₂ is smaller than h (height of the block) and thus the block is exposed to the atmosphere.

Q. Find the minimum value of height h₁ (in situation 1), for which the block just starts to move up?    

The reaction in which sodium cyanide is used is

Molarity of liquid HCl with density equal to 1.17 g/cc is

Which one of the following proteins transports oxygen in the blood stream?

Orthophosphoric acid is

The equilibrium constant for the following reaction will be 3 A + 2 B → C

A system is said to be in thermodynamic equilibrium when it is in

If the truth values of statements p,q,r are True, True and False respectively

Statement-1: Statement ~(p∨q)∧(p∨~r)∧(~p∨~q) is false.

Statement-2: For given truth values ~(p∨q) is false, (p∨~r)  is true, (~p∨~q) is false.

Let f:(−∞,0]→[1,∞) be defined a  then f(x) is

Tangents are drawn from the point (α,β) to the hyperbola 3x²−2y²=6 and are inclined at angles θ and ϕ to the X
-axis. If  tanθ⋅tanϕ=2, then β²−2α²=

If  then which of the following is not true

The number of positive integral solutions of  is

if  are non-coplanar unit vectors such that  are non-parallel, then the angle between  is

 is equal to

Assuming the sum and the products given below are defined, which of the following is false for matrices?

The function f(x) = tan x/x for x ≠ 0 ; f (0) = 1 at x = 0 is

If f : R → R is defined by f x = 2 x + | x | then f (3x) − f (-x)   − 4 x =

If f(x)   = e ^-1/x² , x ≠ 0, and f(0) = 0 then f ′(0)    is

∫[(1)/(4x²+9)]dx =