Alpha particle is: MCQ with Answer and Explanation

Explanation:
A concave mirror forms real and inverted images in most positions. The only exception is when the object is placed very close to the mirror, specifically between the pole (P) and the principal focus (F). In this position, the reflected rays diverge, forming a virtual, erect, and magnified image behind the mirror. This is why concave mirrors are used as shaving or makeup mirrors.

Explanation:
R_t = R₀(1+α t). 6 = 4(1+0.004 t) => 1.5 = 1+0.004t => 0.5=0.004t => t=125°C.

Explanation:
h = ½gt² ⇒ t ∝ √h. If h' = 4h, t' = √4 × t = 2t. Time doubles when height quadruples. Memory aid: 'Free fall: t ∝ √h; 4× height ⇒ 2× time'. Kinematics proportionality frequently tested in competitive exams.