Practice question
Question
Vectors a\=7i^+2j^ and b\=−3i^+4j^ are given. What is the magnitude of a×b?
Explanation
a×b = |i^j^k^720−340| = k^(7×4−2×(−3)) = k^(28+6) = 34k^. Magnitude = 34. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 34. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.