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Induced emf (electromotive force) refers to the voltage generated across a conductor or circuit due to a changing magnetic field, as explained by Faraday's laws of induction. This voltage drives the flow of induced current when the circuit is complete.

The ampere is a fundamental SI base unit, representing electric current, and is one of the seven base units used in physics

A. Reduce the friction of fluid. The pointed front of a boat or airplane is designed to minimize drag and reduce the frictional resistance as it moves through water or air, enhancing efficiency and improving performance.

Equivalent \(\, emf \, E_{eq} = 1.5 \, \text{V} \, (\text{same as single cell})\). Equivalent \(\, internal \, resistance \, r_{eq} = \frac{1}{2} = 0.5 \, \Omega \, (\text{parallel})\). Total \(\, resistance \, R_{total} = r_{eq} + 2 = 2.5 \, \Omega\). Current \(\, I = \frac{E_{eq}}{R_{total}} = \frac{1.5}{2.5} = 0.6 \, \text{A}\).

LASER stands for Light Amplification by Stimulated Emission of Radiation. It works when an incoming photon makes an excited electron release another identical photon, producing a coherent, highly focused beam of light.

The velocity-time graph has three stages: 0 - 10s: constant \(12 \, \text{m/s}\) 10 - 14s: deceleration from \(12 \, \text{m/s}\) to \(0 \, \text{m/s}\) (last stage) The area of the triangle gives the distance in the last stage: \(\text{Area} = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times (14 - 10) \, \text{s} \times 12 \, \text{m/s}\) \(= \frac{1}{2} \times 4 \times 12 = 24 \, \text{m}\).

1a. Tables of values M(g) W\(_1\)(g) W\(_2\)(g) W\(_3\)(g) U = (W\(_1\) - W\(_2\)(g) V = (W\(_1\) - W\(_3\)(g) 5.0 5.00 4.20 4.70 0.80 0.30 10.0 10.00 7.90 8.60 2.10 1.40 15.0 15.00 12.75 13.50 2.25 1.50 20.0 17.10 17.10 16.40 2.90 3.60 25.0 22.10 22.10 21.40 2.90 3.60 S = \(\frac{y_2 - y_1}{x_2 - x_1}\) = \(\frac{3 - 0.8}{2.8 - 1.4}\) = \(\frac{11}{7}\) = 1.57. Precaution (i) I carefully avoided parallax error while reading the scale of the spring balance to ensure accurate measurements. (ii) I checked and accounted for any zero error on the spring balance before taking measurements. (iii) I handled the liquid carefully to prevent any splashing, which could lead to loss of material or inaccurate readings. (iv) I ensured that the object did not touch the bottom or sides of the beaker to avoid interference with the force readings. (v) I thoroughly cleaned the object (mass) before dipping it into the liquid to prevent contamination or alteration of the liquid's properties. bii) Law of Floatation: The law of floatation states that an object will float in a fluid if its weight is equal to the weight of the fluid it displaces. For a floating object, the weight of the object is balanced by the upward buoyant force.

This process disrupts the alignment of magnetic domains, effectively demagnetizing the bar.

2a. Table of observations D(cm) D\(^2\)(cm\^2\) X\(_1\)(cm) L = (X\(_1 - X_2\)) L\(^2\)(cm\(^2\)) 100 10000 80.50 62.20 3868.8 90 8100 70.20 51.20 2621.4 80 6400 59.10 39.10 1528.8 70 4900 46.70 24.70 610.09 60 3600 29.00 21.40 457.96 S = \(\frac{y_2 - y_1}{x_2 - x_1}\) = \(\frac{6250 - 3250}{100 - 60}\) = \(\frac{3000}{40}\) = 75 K = \(\frac{\text{s}}{4}\) = \(\frac{75}{4}\) = 18.75 Precautions: (i) I carefully avoided parallax error by ensuring my eyes were directly in line with the markings on the metre rule while taking measurements to improve accuracy. (ii) I adjusted the setup and focused precisely to ensure a sharp and well-defined image was formed on the screen, minimizing errors due to blurriness or misalignment. (iii) I made sure that the experimental apparatus was stable and free from vibrations to avoid any disturbance during measurements. (iv) I ensured that the metre rule was properly calibrated and positioned perpendicular to the setup to prevent measurement inaccuracies due to angle errors. bi. A real image is formed when light rays converge and meet at a point, allowing it to be projected onto a screen. It is typically inverted relative to the object, as seen in concave mirrors or convex lenses when the object is beyond the focal point. On the other hand, a virtual image is formed when light rays appear to diverge from a point but do not actually meet. This type of image cannot be projected onto a screen and is always upright, as seen in plane mirrors or convex mirrors. bii. See diagram above.

Pressure is defined as force per unit area. In the context of gas molecules colliding with the walls of a container, the force exerted by the gas can be understood as the rate at which momentum is transferred to the walls. As gas molecules collide with the walls, they change momentum, and this change occurs over time. Thus, the pressure can be described as the rate of change of momentum (change in momentum per collision multiplied by the number of collisions per second) divided by the area over which the collisions occur.

(a) A thermometric liquid is a liquid used in thermometers to measure temperature. It expands and contracts uniformly with changes in temperature, allowing for accurate readings. (ii) I. Narrow Bore Reason: Allows precise measurement by controlling the movement of the thermometric liquid, ensuring quick and accurate readings II. Thin Wall of the Bulb Reason: Enhances thermal conductivity, enabling faster heat transfer for quicker and more accurate temperature readings. (b) Heat is a measure of the change in total internal energy in a body while temperature is a measure of the average kinetic energy of a molecule of the body. (c) Evaporation leads to cooling for these reasons: Energy Absorption: Molecules at the surface absorb energy to break free, often from the liquid and its surroundings. Loss of High-Energy Molecules: Higher-energy molecules evaporate, reducing the average kinetic energy of the remaining liquid. Temperature Decrease: As the average kinetic energy drops, the temperature of the liquid decreases, resulting in cooling. (d)(i) Given: P = 2000W, \(\theta\) = 20ºC, t = 2 mins = 120 secs. P x t = mc\(\Delta\)\(\theta\) m = \(\frac{P \times t}{c \times \Delta \theta}\) m = \(\frac{2000 \times 120}{4200 \times (100 - 20)}\) = 0.714 kg Also, Pt = ml l = \(\frac{Pt}{m}\) where m = 45% of 0.714, t = 6mins = 360secs l = \(\frac{2000 \times 60 \times 6}{0.714 \times 0.45}\) = 2.29 x 10\(^6\)Jkg\(^{-1}\) (d)(i) Assumption made: there is no loss of heat to the surroundings, and the heat capacity of the material of the kettle is negligible.

The maximum displacement of particles from equilibrium position in a wave motion is known as "amplitude".

A rainbow is formed by the DISPERSION of sunlight by spherical raindrops floating in the air.

Object distance (u) = -25 cm (negative because the object is in front of the mirror) Image distance (v) = +5 cm (positive because the image is behind the convex mirror) Using \(\frac{1}{f}\) = \(\frac{1}{u}\) + \(\frac{1}{v}\) \(\frac{1}{f}\) = \(\frac{1}{-25}\) + \(\frac{1}{5}\) f = \(\frac{25}{4}\) = 6.250cm.

The Power is given by: P = \(\frac{1}{f}\) f = 20cm → 0.2m P = \(\frac{1}{0.2}\) = 5 dioptres