PH | MCQs

Explanation

Acceleration is related to force, mass, and change in velocity (from Newton’s 2nd Law).

It has no relation with temperature, which is a thermal property.

Explanation

Calculate the second frequency. Divide the first frequency by the number of parts.

1/4=0.25     

Explanation

The time period of a simple pendulum is independent of its mass.

It depends on length and acceleration due to gravity:

T = 2π√L/g

Explanation

The acceleration of a particle moving in a uniform circular motion is directed towards the center of the circle and is given by:

a = v^2 / r

This is known as centripetal acceleration.

Explanation

When a spherical ball rolls without slipping:

Total energy (E) = Kinetic energy (K) + Rotational energy (U)

K = (1/2)mv^2

U = (1/2)Iω^2 = (1/5)mv^2 (for a sphere)

E = K + U = (1/2)mv^2 + (1/5)mv^2 = (7/10)mv^2

Fraction of energy associated with rotation:

U/E = ((1/5)mv^2) / ((7/10)mv^2) = 2/7

Explanation

Energy of one photon (E) = hc / λ

h = 6.626 × 10^-34 Js

c = 3 × 10^8 m/s

λ = 4961 Å = 4961 × 10^-10 m

E = (6.626 × 10^-34 Js × 3 × 10^8 m/s) / (4961 × 10^-10 m)

= 4.007 × 10^-19 J

Number of photons required to do 1 J of work:

n = 1 J / (4.007 × 10^-19 J)

= 2.4961 × 10^18

Explanation

Total mechanical energy (E) = (1/2) × m × ω^2 × A^2

ω = 2π / T = 2π / 0.20 s = 10π rad/s

m = 40 g = 0.04 kg

A = 2.0 cm = 0.02 m

E = (1/2) × 0.04 kg × (10π rad/s)^2 × (0.02 m)^2

= 8.0 × 10^-3 J

Explanation

Using the Heisenberg Uncertainty Principle:

ΔE * Δt >= h/4π

where ΔE = h * Δv (energy uncertainty) and Δt = 10^(-8) s (lifetime)

h * Δv * 10^(-8) >= h/4π

Δv >= 1/(4π * 10^(-8))

≈ 8 x 10^6 Hz

Explanation

Pressure is typically measured in units of force per unit area.

In the Imperial system, pressure is commonly measured in Pounds per Square Inch (PSI).

This is a widely used unit of pressure in engineering, physics, and many other fields.

Other common units of pressure include:

• Atmospheres (atm)
• Bars
• Pascals (Pa)
• Torr

Explanation

A free-falling object near Earth's surface accelerates at approximately 9.80 m/s² due to gravity.

This is known as the acceleration due to gravity (g).