Correct Answer: B. Brightness Of Y will remain constant

Explanation

Diagram above shows a Parallel circuit If one of the parallel path is broken, current will continue to flow in other parts. Voltage is the same across each component of the parallel circuit. The brightness of a light bulb is given by its power. P = I2R, and so brightness depends on current and resistance. Hence; the brightness of Y will not be affected except for a variation in resistance property.

Explanation

(a) - Sum of forces in one direction is equal to the sum of forces in opposite direction. - Sum of anti-clockwise moments about a point is equal to the sum of clockwise moment about the same point.

(b) Diagram:

Method: Suspend the metre rule on a knife edge. Adjust its position until it balances horizontally. Note the balance point G. Then suspend a mass M on one side of the rule. Adjust the rule until it balances horizontally again. Read and record X and Y as in the diagram above. According to the principle of moment:

Mgx = Mgy

m = \(\frac{Mgy}{gx} = \frac{My}{x}\)

m = mass of rule

Precautions

- Avoid drought

- Avoid parallax in reading the metre rile

(c)(i) Deceleration a = \(\frac{u - v}{t} = \frac{20 - 0}{0.1}\) = 200ms

Resistance = ma = 0.12 x 200 = 24N

(ii) Distance, s \(\frac{u^2 - v^2}{2a} = \frac{20^2 - O^2}{2 \times 200} = \frac{400}{400}\)

= 1.0m

Correct Answer: B) forward baised

Correct Answer: A. 2 diopters

Explanation

The patient cannot see clearly an object closer than 50 cm

Therefore, the patient needs a lens that would enable him see clearly, objects placed 25 cm from the lens

So, we take the object to a distance of 25 cm from the lens so that the image forms at 50 cm in front of the lens

u=25cm ;v=-50cm (virtual image); p=

\(\frac{1}{f}\)=\(\frac{1}{u}\) + \(\frac{1}{v}\)

⇒\(\frac{1}{f}\) =\(\frac{1}{50}\)

⇒\(\frac{1}{f}\) = \(\frac{1}{25}\)-\(\frac{1}{50}\)

⇒\(\frac{1}{f}\) = f = 50cm =0.5cm

⇒\(\frac{1}{f}\) = \(\frac{2-1}{50}\)

p = \(\frac{1}{f}\)

p = \(\frac{1}{0.5}\)

p = 2 diopters

; The patient needs a converging lens with a power of 2 diopters

Correct Answer: D. 0.75

Correct Answer: C. Tungsten filament lamp

Explanation

An incandescent light source is a type of light source that produces light by heating a material until it glows. The material that is heated is usually a metal, such as tungsten. Fluorescent lamps, LED lamps, and neon lamps are all examples of non-incandescent light sources.

Fluorescent lamps produce light by passing an electric current through a gas, which causes the gas to emit ultraviolet light. The ultraviolet light then causes a coating on the inside of the lamp to fluoresce, which produces visible light.

LED lamps produce light by passing an electric current through a semiconductor material, which causes the material to emit photons. The photons then produce visible light.

Neon lamps produce light by passing an electric current through a gas, which causes the gas to emit visible light.

Correct Answer: C. 3.4 x 10^-5m³

Explanation

V = \(\frac{m}{p}= \frac{170}{8.5 x 10^{-3}}\) = 0.02

= \(\Delta\)\(\frac{\delta V}{V \delta T}\)

\(\delta V\) = \(\Delta\) x V x \(\delta\)T

= 5.7 x 10^-5 x 0,02 x 30

= 0 3.42 x 10^-5

Correct Answer: C. 15.09cm³

Explanation

linear expansivity = \(\frac {V_2 - V_1}{V_1 {\times} {\Delta}{\theta}}\)

3 x 2 x 10^-5 =\(\frac {V_2 - 15}{15 {\times} (100 - 0)}\)

V₂ = 15.09cm³

Explanation

(a) Particles used in explaining the wave nature of matter are: hydrogen atom or proton, helium atom, electrons, neutron and helium nuclei or apha particles.

(b) Inventions based on the wave nature of water devices are:

- Electron microscope and scanning tunneling microscope (STM).

Explanation

E \(\frac{Fl}{Ae}\)

= \(\frac{35 \times 10^3 \times 50 \times 10^{-2}}{4 \times 10^{-4} \times 0.25 \times 10 ^{-3}}\)

= 1.75 x 10\(^{11}\)Nm\(^{-2}\)