1. The pair of lines whose direction cosines are given by the equations 3*l*+*m*+5*n*=0, 6*mn*-2*nl*+5*lm*=0 are :

(a) parallel

(b) perpendicular

(c) inclined at cos^{-1 }(1/6)

(d) none of these

2. The angle between any two diagonals of a cube is :

(a) cos θ = √3/2

(b) cos θ = 1/√2

(c) cos θ = 1/3

(d) cos θ = 1/√6

3. The point equidistant from the four points (a,0,0), (0,b,0), (0,0,c) and (0,0,0) is :

(a) (a,b,c)

(b) (a/2,b/2,c/2)

(c) (a/3,b/3,c/3)

(d) None of these

4. The line joining the points (1,1,2) and (3, -2 ,1) meets the plane 3*x*+2*y*+*z* = 6 at the point :

(a) (1,1,2 )

(b) (3,-2 ,1)

(c) (2,-3,1 )

(d) (3,2 ,1)

5. The plane passing through the point (5,1,2) perpendicular to the line

2(*x*-2) = *y*-4 = *z*-5 will meet the line in the point :

(a) (1,2 ,3)

(b) (2,3,1 )

(c) (1,3 ,2)

(d) (3,2,1 )

**Be a Part of The New & Next**

**Share the Knowledge**