🔭 physics

1. Problem: Understand properties of Wi-Fi signals and related wave concepts. 2. (a)(i) Similarity of Wi-Fi signals at 2.4 GHz and 5.2 GHz:

1. **Problem Statement:** Explain the concepts of total internal reflection, refraction, and reflection with examples using air-aluminium and air-glass boundaries. Also, state two

1. **State the problem:** We are given a filament lamp with a voltage rating of $240$ V and a resistance of $960$ ohms. We need to find the current taken by the lamp and its power

1. Stating the problem: Calculate the resistance $R$ of a 200 m iron wire with resistivity $\rho = 1.6 \times 10^{-7}$ $\Omega$m and circumference $C = 0.02$ m. 2. Find the radius

1. Stating the problem: We need to find the resistance $R$ of a 2000 m long iron wire, given its resistivity $\rho = 1.0 \times 10^{-7} \ \Omega m$ and its circumference $C = 0.02

1. **Problem Statement:** Calculate the resistance $R$ of a 1000 m long aluminum cable with a circumference $C=0.015$ m and aluminum resistivity $\rho=2.82 \times 10^{-8}$ $\Omega

1. The problem is to solve Kirchoff's simultaneous equations using determinants: \[I_1 + 8 I_2 + 3 I_3 = -31\]

1. The problem involves a hexagon with vertices A, B, C, D, E, F and edges AB, BC, CD, DE, BF, AF. 2. Given lengths: AB = BC = a, EF = DE = a, AF = 3W.

1. Problem 3: An electric kettle has a resistance of 30 Ω. What current will flow when connected to a 240 V supply? Also, find the power rating of the kettle. 2. Using Ohm's Law, c

1. **State the problem:** We are given a system of three simultaneous linear equations derived from Kirchhoff's laws: $$I_1 + 8I_2 + 3I_3 = -31$$

1. **State the problem:** A car of mass $m = 800$ kg moves around a circular track of radius $r = 50$ m at a speed $v = 10$ m/s. Find the required centripetal force $F_c$. 2. **Rec

1. Problem 1: Determine the resistance when current $I=0.8$ A and voltage $V=20$ V. Using Ohm's law: $$R = \frac{V}{I} = \frac{20}{0.8} = 25\,\Omega$$

1. The resistance $R$ of a wire is calculated using the formula $R=\rho \frac{L}{A}$ where $\rho$ is resistivity, $L$ is length, and $A$ is cross-sectional area. 2. For Question 1,

1. The problem states a mass of 150 kilograms. 2. Since no further operation or context is given, the mass is simply 150 kg.

1. **Stating the problem:** We are given a velocity-time graph for a cycle showing velocity changes over 20 seconds.

1. **Stating the Problem:** We have a solid aluminum sphere and a solid iron sphere balanced on an equal-arm balance. The iron sphere has a radius of $r_{Fe} = 2.00$ cm. Given the

1. Problem 22 states: Given the Earth's mean radius $r_\text{Earth} = 6.37 \times 10^{6} \ m$ and Moon's mean radius $r_\text{Moon} = 1.74 \times 10^{8} \ cm$, calculate:

1. **State the problem:** We want to find the density of lead in SI units (kg/m\(^3\)) given the mass \( m = 23.94 \) g and the volume \( V = 2.10 \) cm\(^3\). 2. **Convert the mas

1. **State the problem:** We need to find the SI units of the constant $G$ in Newton's law of universal gravitation given by $$F=\frac{GMm}{r^2}.$$ Here, $F$ is force with units $\

1. **Problem statement:** We have two spheres cut from uniform rock. Sphere 1 has radius $r_1 = 4.50$ cm. The mass of sphere 2 is five times the mass of sphere 1. We want to find t

1. **Calculate the average density of the Earth.** The average density $\rho$ is defined as mass divided by volume: