The azimuthal quantum number (l) determines the shape of the orbital (s, p, d, f)

Resistance R = ρL/A. When length doubles, L becomes 2L and area becomes A/2 (volume constant). New R = ρ(2L)/(A/2) = 4ρL/A = 4R

Blue light has shorter wavelength and is scattered more by atmospheric molecules (Rayleigh scattering)

Lorentz force F = q(v × B). When v is parallel to B, the cross product is zero, so no force acts

Vertical component of velocity: u_y = 20 sin(45°) = 20/√2 = 10√2 m/s. Maximum height h = u_y²/(2g) = (10√2)²/(2×10) = 200/20 = 10 m.

The first law of thermodynamics (ΔU = Q - W) states that energy cannot be created or destroyed, only transferred. It is based on conservation of energy.

# Transformer Voltage Calculation

A transformer changes voltage based on the ratio of turns in its primary and secondary coils.

Step 1: Identify the Transformer Equation

For an ideal transformer, the voltage ratio equals the turns ratio between the primary and secondary coils.

Step 2: Substitute Given Values and Solve

We have: \(N_{\text{primary}} = 500\) turns, \(N_{\text{secondary}} = 100\) turns, and \(V_{\text{primary}} = 220\text{ V}\)

The secondary voltage is 44 V.

Answer: (B) 44 V

# SI Units of Momentum and Impulse

Momentum and impulse are related concepts in physics, but they represent different physical quantities with distinct SI units.

Momentum is defined as the product of mass and velocity. Using the fundamental SI units of mass (kg) and velocity (m/s), we can derive momentum's unit:

Impulse is defined as the product of force and time, or equivalently, the change in momentum. Using the SI unit of force (Newton = N = kg·m/s²) and time (seconds = s):

Alternatively, since impulse equals change in momentum: \[\text{Impulse} = \Delta p = \text{kg·m/s (same as momentum)}\]

Both perspectives confirm that impulse is measured in N·s, which is equivalent to kg·m/s.

The correct answer is (C): kg·m/s and N·s — momentum is measured in kg·m/s and impulse is measured in N·s.

Stars appear as point sources. Turbulent layers in the atmosphere refract starlight randomly, causing intensity variations (twinkling). Planets appear as extended sources, so refraction averaging effect minimizes visible twinkling.

Carnot efficiency: η = 1 - (T_cold/T_hot) = 1 - (300/400) = 1 - 0.75 = 0.25 = 25%. This is the theoretical maximum for any heat engine.