If two sets A and B are having 39 elements in common, then the number of elements common to each of the sets A x B and B x A are

(a) 2³⁹ 

(b) 39²

(c) 78 

(d) 351

The sides of a rectangle are 7.01m and 12m. Taking the significant figures into account , the area of the rectangle is :

(A) 84m² 

(B) 84.1m² 

(C) 84.00m² 

(D) 84.12m²

The value of lim (x → ∞) [x√(x² + 4) – √(x⁴ + 16)] is equal to

(A) 4

(B) 8

(C) 2

(D) 16

If vector a, b, c are non planar vectors, then [vector a x b,b x c, c x a] is equal to

(A) 0

If vector a, b, c are non three non-coplanar unit vectors, then [vector a b c] is equal to 

(A) ±2

(B) ±3

(C) ±1

(D) 2

Which element is not in first transition series? 

(A) Fe 

(B) V 

(C) Ag 

(D) Cu

Which reagent is capable of giving test both of Aldehyde and Ketones? 

(A) Tollen reagent 

(B) Fehling solution 

(C) 2, 4 dinitrophenylhydrazine 

(D) Shift reagent

Which reaction will not occur out of the following?

(A) Fe + H₂SO₄ → H₂ + FeSO₄ 

(B) Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag 

(C) 2KBr + I₂ → 2KI + Br₂ 

(D) CuO + H₂ → Cu + H₂O

The population inversion in helium-neon laser is produced by 

(a) photon excitation 

(b) chemical reaction 

(c) inelastic atomic collision 

(d) electron excitation 

The population inversion in helium-neon laser is produced by 

(a) photon excitation 

(b) chemical reaction 

(c) inelastic atomic collision 

(d) electron excitation