Why does a person feel lighter when standing on a weighing scale inside a freely falling lift?

The normal reaction on the person decreases

Gravity becomes zero everywhere

Medium Free Competitive Exams Railway

Railway General Science Quiz

Physics, Chemistry and Biology questions for Railway competitive exams

43 Questions

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40% To pass

1.00 Marks / correct

Instructions

This quiz has 43 questions.
There is no time limit on this quiz.
You need 40% to pass.
There is no negative marking.
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Correct answers and explanations are shown after you submit.

Sample Questions & Answers

A preview of 12 questions from this quiz, each with the correct answer and a written explanation. Attempt the full, timed quiz to be scored and earn XP.

Question 1
A train covers 180 km in 3 hours. What is its average speed?
- 40 km/h
- 50 km/h
- 60 km/h Correct answer
- 90 km/h
Explanation: Average speed = distance/time = 180/3 = 60 km/h.
Question 2
A force of 20 N moves an object 5 m in the direction of the force. What work is done?
- 25 J
- 50 J
- 100 J Correct answer
- 200 J
Explanation: Work = force × displacement = 20 × 5 = 100 J.
Question 3
Which SI unit is used for power?
- Joule
- Watt Correct answer
- Newton
- Pascal
Explanation: Power is the rate of doing work, and its SI unit is the watt.
Question 4
If the resistance of a conductor remains constant and its voltage is doubled, what happens to the current?
- It becomes half
- It remains unchanged
- It doubles Correct answer
- It becomes four times
Explanation: By Ohm's law, I = V/R. With constant resistance, doubling voltage doubles current.
Question 5
A 10 ohm resistor is connected to a 20 V supply. What current flows through it?
- 0.5 A
- 1 A
- 2 A Correct answer
- 4 A
Explanation: Ohm's law gives I = V/R = 20/10 = 2 A.
Question 6
Which quantity is measured in pascals?
- Energy
- Pressure Correct answer
- Electric charge
- Frequency
Explanation: The pascal is the SI unit of pressure.
Question 7
Why does a person feel lighter when standing on a weighing scale inside a freely falling lift?
- Mass decreases
- Gravity becomes zero everywhere
- The normal reaction on the person decreases Correct answer
- Air pressure increases
Explanation: During free fall, the lift and person accelerate downward together, reducing the normal reaction measured by the scale.
Question 8
Which form of energy is stored in a compressed spring?
- Chemical energy
- Elastic potential energy Correct answer
- Nuclear energy
- Sound energy
Explanation: A compressed spring stores mechanical energy as elastic potential energy.
Question 9
A convex lens is commonly used in a magnifying glass because it can form which image when the object is within its focal length?
- Real and inverted
- Virtual, erect and magnified Correct answer
- Real and diminished
- Virtual and inverted
Explanation: For an object placed within the focal length of a convex lens, the image is virtual, erect and magnified.
Question 10
Which phenomenon explains the bending of light when it passes obliquely from air into glass?
- Reflection
- Diffraction
- Refraction Correct answer
- Polarization
Explanation: Refraction is the change in direction of light due to a change in its speed when it enters another medium.
Question 11
A sound wave has a frequency of 500 Hz. How many complete vibrations occur in 2 seconds?
- 250
- 500
- 1,000 Correct answer
- 2,000
Explanation: Number of vibrations = frequency × time = 500 × 2 = 1,000.
Question 12
Which device converts electrical energy into mechanical rotational energy?
- Electric motor Correct answer
- Transformer
- Electric cell
- Galvanometer
Explanation: An electric motor converts electrical energy into mechanical motion.