Let a =2 i -7 j +5 k , b = i + k , c = i +2 j -3 k be three given vectors. If r is a vector such that r a = c...

Question

Let a =2 i -7 j +5 k , b = i + k , c = i +2 j -3 k be three given vectors. If r is a vector such that r a = c a and r b =0, then | r | is equal to :

Accepted Answer

(D)

JEE Main 2023 Mathematics question