Upwards
Downwards
Right
Left
Correct answer is D
No explanation has been provided for this answer.
1.5V, 7.50Ω
1,5V, 0.83Ω
4.5V, 7.50Ω
4.5V, 0.83Ω
Correct answer is B
Since the cells are connected in parallel the net e.m.f is that of one cell, E.
However the effective internal resistance should be added as parallel resistance.
=> 1/v + 1/25 + 1/25 + 1/25 = 1.2
∴ v = 0.83Ω
∴ Effective e.m.f and internal resistance are respectively = 1.5V and 0.83Ω
1600N
400N
160N
40N
Correct answer is A
The fundamental frequency is related to tension as
F ∝ √T
| => | F | = K |
| √T |
| ∴ | F1 | = | F2 | => | 250 | = | 500 | √T1 | √T2 | √400 | √T2 |
| ∴√T2 = | 500 | √400 = 2 x 20 |
| 250 |
∴ T2 = 402 = 1600N
8/3
3/2
2/3
3/8
Correct answer is C
Ratio of their linear expansion = ∝1/∝2= 3:4.
When heated to the same temperature range, the ratio of their increase in length e1/e2 = 1:2
But the increase in length of
1 = e1 = ∝1l1Δθ and increase i length of
2 = e2 = ∝2l2Δθ
| => | e1 | = | ∝1l1Δθ | = | ∝1l1 | = | 1 |
| e2 | ∝2l2Δθ | ∝2l2 | 2 |
| But | ∝1 | = | 3 | , ∴ | 3 | x | l1 | = | 1 |
| ∝2 | 4 | 4 | l2 | 2 |
=> 6l1 = 4l2
| ∴ | l1 | = | 4 | = | 2 | OR 2 : 3 | l2 | 6 | 3 |
A blacksmith heated a metal whose cubic expansivity is 6.3 x 10-6K-1. The area expansivity is
2.0 x 10-6K-1
2.1 x 10-6K-1
4.2 x 10-6K-1
6.3 x 10-6K-1
Correct answer is C
If the lineal expansivity = ∝
=> area expansivity β= 2∝.
And cubic expansivity δ = 3∝.
=> 6.3 x 10-6 = 3∝
∴ ∝ =
| ∴ ∝ = | 6.3 x 10-6 | = 2.1x 10-6 |
| __3 |
∴ Area = 2∝ = 2 x 2.1x10-6
= 4.2 x 10-6K-1
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