Tahsili Physics — Questions and Answers
Question 1: A car accelerates uniformly from rest to 20 m/s in 5 seconds. What is its acceleration?
- 2 m/s²
- 4 m/s² (Correct answer)
- 5 m/s²
- 100 m/s²
Correct answer: 4 m/s²
Acceleration = (final velocity - initial velocity) / time = (20 - 0) / 5 = 4 m/s². The car increases its velocity by 4 meters per second every second.
Question 2: What is the SI unit of force?
- Joule
- Watt
- Newton (Correct answer)
- Pascal
Correct answer: Newton
The Newton (N) is the SI unit of force. 1 N = 1 kg⋅m/s². It is defined as the force needed to accelerate 1 kg of mass by 1 m/s². Named after Sir Isaac Newton.
Question 3: A 5 kg object is lifted 10 meters vertically. How much work is done against gravity? (g = 10 m/s²)
- 50 J
- 500 J (Correct answer)
- 100 J
- 5000 J
Correct answer: 500 J
Work = Force × Distance = mgh = 5 × 10 × 10 = 500 Joules. The force applied equals the weight (mg) and the displacement is the height lifted.
Question 4: What is the frequency of a wave with wavelength 2 meters traveling at 340 m/s?
- 680 Hz
- 170 Hz (Correct answer)
- 340 Hz
- 85 Hz
Correct answer: 170 Hz
Using v = fλ: f = v/λ = 340/2 = 170 Hz. This is the frequency of a sound wave with a 2-meter wavelength traveling at the speed of sound in air.
Question 5: According to Ohm's Law, if a circuit has a voltage of 12V and resistance of 4Ω, what is the current?
- 48 A
- 3 A (Correct answer)
- 0.33 A
- 16 A
Correct answer: 3 A
Ohm's Law: V = IR, so I = V/R = 12/4 = 3 Amperes. Ohm's Law describes the linear relationship between voltage, current, and resistance in a conductor.
Question 6: What type of energy does a compressed spring have?
- Kinetic energy
- Elastic potential energy (Correct answer)
- Thermal energy
- Chemical energy
Correct answer: Elastic potential energy
A compressed spring stores elastic potential energy. This energy is stored due to the deformation of the spring and can be converted to kinetic energy when released. PE = ½kx², where k is the spring constant and x is the compression.
Tahsili Physics
A car accelerates uniformly from rest to 20 m/s in 5 seconds.
What is its acceleration?