JEE Main entrance exam Question Bank Solutions

Which one of the following reactions of xenon compounds is not feasible?

If NaCl is doped with 10^–3 mol % of SrCl₂ calculate the concentration of cation vacancies.

The correct order of bond strength is ______.

Among the following ions, which one has the highest paramagnetism?

Which of the following is not paramagnetic?

Match items of List - I with those of List - II:

Choose the most appropriate answer from the options given below:

The parameters of the unit cell of a substance are a = 2.5, b = 3.0, c = 4.0, α = 90°, β = 120°, γ = 90°. The crystal system of the substance is ______.

Let the mean and the variance of 5 observations x₁, x₂, x₃, x₄, x₅ be `24/5` and `194/25` respectively. If the mean and variance of the first 4 observation are `7/2` and a respectively, then (4a + x₅) is equal to ______.

Let b₁, b₂, b₃, b₄ be a 4-element permutation with b_i ∈ {1, 2, 3, .......,100} for 1 ≤ i ≤ 4 and b_i ≠ b_j for i ≠ j, such that either b₁, b₂, b₃ are consecutive integers or b₂, b₃, b₄ are consecutive integers. Then the number of such permutations b₁, b₂, b₃, b₄ is equal to ______.

The number of values of α ∈ N such that the variance of 3, 7, 12, α, 43 – α. is a natural number is ______.

`lim_(x→0^+)(int_0^(x^2)(sinsqrt("t"))"dt")/x^3` is equal to ______.

If ¹P₁ + 2. ²p₂ + 3. ³p₃ + ....... 15. ¹⁵P₁₅ = ^qP_r – s, 0 ≤ s ≤ 1, then ^q+sC_r–s is equal to ______.

The number of three-digit even numbers, formed by the digits 0, 1, 3, 4, 6, 7 if the repetition of digits is not allowed, is ______.

If the letters of the word 'MOTHER' be permuted and all the words so formed (with or without meaning) be listed as in a dictionary, then the position of the word 'MOTHER' is ______.

If `lim_(x -> 1) (x + x^2 + x^3|+ .... + x^n - n)/(x - 1)` = 820, (n ∈ N) then the value of n is equal to ______.

`lim_(x→-1) (x^3 - 2x - 1)/(x^5 - 2x - 1)` = ______.

`lim_(x→∞)((x + 7)/(x + 2))^(x + 4)` is ______.

Ten different letters of an alphabet are given. Words with five letters are formed from these given letters. Determine the number of words which have at least one letter repeated.

The value of `lim_(x→0)(sin(ℓn e^x))^2/((e^(tan^2x) - 1))` is ______.

The number of real solutions of `x - 1/(x^2 - 4) = 2 - 1/(x^2 - 4)` is ______.