Measurements

Written by Dr. Hamza Farooq (Physics)

Class 11 · Physics · 8 questions

Name: ____________________ Date: ____________

Which of these is a derived unit?
- A Metre
- B Second
- C Kilogram
- D Newton
The dimensions of velocity are:
- A [L² T⁻¹]
- B [L T⁻¹]
- C [L T⁻²]
- D [M L T⁻¹]
How many significant figures are in 0.004050?
- A 3
- B 6
- C 2
- D 4
A length is measured as 2.50 m with an uncertainty of 0.05 m. The percentage uncertainty is:
- A 0.2 percent
- B 5 percent
- C 0.05 percent
- D 2 percent
Which quantity has the dimensions [M L² T⁻²]?
- A Pressure
- B Force
- C Energy
- D Power
The SI unit of luminous intensity is the:
- A Lux
- B Lumen
- C Candela
- D Watt
Which instrument gives the most precise measurement of the thickness of a thin wire?
- A Screw gauge
- B Measuring tape
- C Vernier calliper
- D Metre rule
A random error can be reduced by:
- A Changing the unit
- B Taking many readings and averaging
- C Using a single reading
- D Ignoring the zero error

Answer key

1. D, 2. B, 3. D, 4. D, 5. C, 6. C, 7. A, 8. B

Newton is kg m/s², built from base units.
Velocity is length divided by time.
Leading zeros do not count. The digits 4, 0, 5, 0 give four significant figures.
0.05 / 2.50 x 100 = 2 percent.
Energy = force x distance = M L T⁻² x L = M L² T⁻².
The candela is the base unit.
A screw gauge reads to 0.01 mm.
Averaging reduces the effect of random variations.