2003 - JAMB Physics Past Questions and Answers - page 2

R.H = Partial Pressure of Water Vapour Presentx100_1S.V.P at temperature of atmosphere

= _10x100_117.50

= 57.14%

Here's how to solve the problem:

1. Understand Resonance in a Closed Tube: Resonance in a closed tube (closed at one end, which is the case as water is poured in) occurs when the length of the air column is a quarter of the wavelength (fundamental frequency) or an odd multiple of a quarter wavelength. The formula for the fundamental frequency is: L = λ/4. Higher resonance points occur at 3λ/4, 5λ/4, etc. We're looking for the maximum height, meaning the air column will be at its first resonance.

2. Calculate the Wavelength (λ): Use the formula: v = fλ, where:

   • v = speed of sound (340

Form the lens formula = ¹/_U + ¹/_V = ¹/_f

=> ¹/₁₀ + ¹/₂₅ = ¹/_f;

∴ (5 + 2) / 50 = ¹/_f

∴ f = ⁵⁰/₇cm

since the image is observed on a screen, it is a real image. Thus magnification

M = ^f/_U-f

= ⁵⁰/₇ x ⁷/₂₀ = 2.5

Two thermal objects are said to be in a thermal equilibrium when the temperature of both objects are equal. Generally, heat flows from an object at a higher temperature to the one at a lower temperature until both temperature are the same, during which the two bodies are said to be in thermal equilibrium

In vibration in a closed pipe/tube as shown in the figure, fundamental note is produced at the first position of resonance. When the length of the air column L = ^λ/₄; => λ = 4L. Since the open end of the tube is taken as an antinode; and closed end as the node.

Thus the associated frequency is given by

f = ^V/_λ = ^V/_4L

∴ f = ^V/_4L

The increase in length of the steel rail is given by

= α 10

= 11 x 10^-6 x 20 x (40 -20)

= 11 x 10^-6 x 20 x 20

= 4.4 x 10^-3

∴ Final length will be original length plus increase in length

= 20 + 4.4 x 10^-3

= 20 + 0.0044

= 20.0044m

The number of images to be observed will be infinite

For a concave mirror to produce an image at infinity, the image has to be place at the principal focus of the mirror

In general intensity of a wave is the rate of flow of energy across unit area normal to the direction of propagation of the wave intensity α¹/_r² where r is the distance away from the point source. Thus if the distance from the point source of the sound wave is doubled, then the intensity will be decreased by a factor of 4