Uniform acceleration: v-t graph is: MCQ with Answer and Explanation

Explanation:
Planck's constant (h) has dimensions [ML²T⁻¹]. Angular momentum (L = mvr) has dimensions [M][LT⁻¹][L] = [ML²T⁻¹], matching exactly. Linear momentum is [MLT⁻¹], force is [MLT⁻²], and torque is [ML²T⁻²]. This dimensional equivalence is fundamental in quantum mechanics, linking wave-particle duality. Memory tip: Both represent 'action' quantities with identical dimensional structure. This concept frequently appears in competitive exams testing dimensional analysis skills.

Explanation:
Law of reflection: angle of incidence = angle of reflection, both measured from normal. So 30°. If angle with mirror is given, convert to normal. Always equal for smooth surfaces.

Explanation:
Pressure cooker seals steam, increasing internal pressure above atmospheric. Higher pressure raises water's boiling point (above 100°C), allowing food to cook at higher temperature, speeding up chemical reactions. Option A is vague; C and D are secondary effects. Memory tip: 'Higher pressure ⇒ higher boiling point ⇒ faster cooking'. This daily-life physics question tests application of pressure-temperature relationship in liquids, frequently appearing in competitive exams. Always recall that phase change temperatures depend on pressure (e.g., water boils below 100°C on mountains).