Question

Fig. I	Fig. II

In figure-I, an air column of length ℓ₁ is entrapped by a column of Hg of length 8 cm. In figure-II length of same air column at the same temperature is ℓ₂. The `ℓ_1/ℓ_2` is:
(1 atm = 76 cm of Hg)

Options

• `1 + 2/19 xx cosθ`

• `1 + 2/19 xx sinθ`

• `1 + 2/21 xx sinθ`

• `21/19`

Answer 1

`bb(1 + 2/19 xx cosθ)`

Explanation:

P₁ℓ₁ a = P₂ℓ₂ a

P₁ = 76 cm of Hg

P₂ = 76 + 8 cosθ

76 × ℓ₁ = (76 + 8 cosθ)ℓ₂

or `ℓ_1/ℓ_2 = (76 + 8 cosθ)/76`

= `1 + (8 cosθ)/76`

= `1 + 2/19 cosθ`