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 :
a)
2.2
b)
0.7
c)
3.6
d)
1.8
a)
2.2
b)
0.7
c)
3.6
d)
1.8
Question ID - 51439 | SaraNextGen Top Answer 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 :
a)
2.2
b)
0.7
c)
3.6
d)
1.8
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 :
|
a) |
2.2 |
b) |
0.7 |
|
c) |
3.6 |
d) |
1.8 |
1 Answer
127 votes
Answer Key / Explanation : (b) -
T1 = 2 sec., T2 = 3/2
For place (1), 
For place (2), 
T = 
= 
= 
⇒ 
= 
⇒ 
= 0.68 
0.7
127 votes
Answer Link
127