The GATE Grind

GATE 2025 MA – Question 32

Calculus · Vector Calculus · 1 mark · Numerical answer

F=(y−z)i+(z−x)j+(x−y)k. S is the outward upper hemisphere x²+y²+(z−1)²=9, 1≤z≤4. Find $\pi^{-1}|\iint_S(\nabla\times F)\cdot n\,dS|$ (integer).

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: 18 to 18

Explanation

Curl F = (−2,−2,−2). Close the hemisphere by the radius-3 disk at z=1 with downward normal. Total flux of a curl through the closed surface is zero. Disk flux = 2×9π=18π; hemisphere flux = −18π. Absolute value divided by π gives **18**.

More Vector Calculus questions

All Vector Calculus questions →