Govt. Exams
Centripetal acceleration a = v²/r = (10)²/5 = 100/5 = 20 m/s².
For capacitors in series: 1/C = 1/C₁ + 1/C₂ = 1/2 + 1/3 = 5/6. Therefore C = 6/5 = 1.2 μF.
At maximum height, v = 0. Using v² = u² - 2gh: 0 = 20² - 2(10)h. 20h = 400. h = 20 m.
The Second Law of Thermodynamics states that entropy of an isolated system increases or remains constant. Heat spontaneously flows from hot to cold, not vice versa, establishing the direction of processes.
Kinetic energy KE = (1/2)mv². When velocity is doubled: KE' = (1/2)m(2v)² = (1/2)m(4v²) = 4 × (1/2)mv² = 4K.
The photoelectric effect occurs when light of frequency greater than or equal to the threshold frequency strikes a metal surface, causing electron emission. It demonstrates the particle nature of light.
Elastic potential energy E = (1/2)kx². 5 = (1/2)k(0.1)². 5 = 0.005k. k = 1000 N/m.
Using v = fλ, where v = 330 m/s and f = 440 Hz. λ = v/f = 330/440 = 0.75 m.
For parallel resistances: 1/R = 1/R₁ + 1/R₂ = 1/10 + 1/20 = 3/20. Therefore R = 20/3 = 6.67 Ω.
When object distance (5 cm) < focal length (10 cm), the object is between the mirror and focus. A concave mirror forms a virtual, erect, and magnified image in this case.