A magnetic compass needle oscillates 30 times per minute at a place where the dip is
PHYSICS · Single correct · CBSE · Physics · Electricity: Magnetic and Heating Effects · Electricity: Magnetic and Heating Effects
Problem
A magnetic compass needle oscillates 30 times per minute at a place where the dip is 45∘, and 40 times per minute where the dip is 30∘. If B1 and B2 are respectively the total magnetic field due to the earth at the two places, then the ratio B1/B2 is best given by:
(1) 1.8
(2) 0.7
(3) 3.6
(4) 2.2