Which instrument measures the speed of rotation of a shaft? MCQ with Answer and Explanation

Explanation:
The angle of dip is the angle the Earth's total magnetic field vector makes with the horizontal surface. At the magnetic equator, the magnetic field lines are perfectly parallel to the ground (0 degrees). At the magnetic poles, the field lines plunge strictly vertically downward (or upward) into the ground, making a 90-degree angle with the horizontal.

Explanation:
F = qvB sinθ, max at θ=90°.

Explanation:
Leading zeros not significant. '450' has three digits, but the trailing zero after decimal is significant (4,5,0). So 3 significant figures. 0.00450 is 3 SF.