Vectors (JEE - 2004

A ray represented by a unit vector u ,is reflected by a plane mirror,whose normal is given by another unit vector v,the reflected ray is along unit vector w. Express w in terms of v,u

2 Answers

11
Mani Pal Singh ·

ANGLE OF INCIDENCE=ANGLE OF REFRACTION
v=w+(-u)/|w-v| ...................(1)

( because v is the angle bisector and it will be in the same direction dividing in the same ratio)

|w-v|=OC=2OP
=2|w|cosθ=2cosθ (w is a unit vector)
substituting in eq 1 we get

v=w-u/2cosθ
2vcosθ=w-u

cosθ=-u.v (because u and v are unit vectors)

so

2v(-u.v)=w-v

w=v-2v(v.w)

1
Pavithra Ramamoorthy ·

hey manipal how do u bring dat sign here?????

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