Question 1

1. In the International System of Units (SI), which unit is used to measure the luminous intensity of a light source?

A) LumenB) LuxC) CandelaD) Watt

Answer

✓ Correct Answer: Option C

Explanation: Solution: The SI base unit of luminous intensity is the Candela (symbol: cd). It measures the luminous power per unit solid angle emitted by a point light source in a particular direction.

Question 2

2. A researcher is calculating the angle subtended by a spherical surface at its center. What is the SI unit for this 'solid angle'?

A) RadianB) SteradianC) Degree

Question 3

3. Which of the following is considered a 'Fundamental Unit' in the SI system?

A) KilogramB) NewtonC) JouleD) Pascal

Answer

✓ Correct Answer: Option A

Explanation: Solution: Fundamental units are the units of base quantities. In SI, there are seven: Meter (m), Kilogram (kg), Second (s), Ampere (A), Kelvin (K), Mole (mol), and Candela (cd). Kilogram is a base unit, while Newton, Joule, and Pascal are derived units.

Question 4

4. A high-speed train travels at a velocity of 180 km/h. What is its speed expressed in the SI unit of velocity (m/s)?

A) 20 m/sB) 30 m/sA) 40 m/sD) 50 m/s

Answer

✓ Correct Answer: Option D

Explanation: Solution: To convert km/h to m/s, multiply the magnitude value by $\frac{5}{18}$: $$180 \times \frac{5}{18} = 10 \times 5 = 50m/s$$

Question 5

5. The pressure exerted by a fluid is measured in Pascals (Pa). Which of the following represents 1 Pascal in terms of base units?

A) $kg \cdot m \cdot s^{-2}$B) $kg \cdot m^{-1} \cdot s^{-2}$C) $kg \cdot m^{2} \cdot s^{-2}$D) $kg \cdot m^{-2} \cdot s^{-1}$

Answer

✓ Correct Answer: Option B

Explanation: Solution: Pressure is Force per unit Area (P = F/A). Units of Force (N) = $kg \cdot m \cdot s^{-2}$ Units of Area = $m^{2}$ Therefore, $$P = \frac{kg \cdot m \cdot s^{-2}}{m^2} = kg \cdot m^{-1} \cdot s^{-2}$$

Question 6

6. An atomic physicist measures the radius of a nucleus to be 1 Angstrom (Å). This length is equivalent to:

A) $10^{-10}m$B) $10^{-9}m$C) $10^{-12}m$D) $10^{-15}m$

Answer

✓ Correct Answer: Option A

Explanation: Solution: By dimension definition, 1 Angstrom (1 Å) is exactly equivalent to $10^{-10}$ meters.

Question 7

7. Which of the following is NOT a unit of distance?

A) Light yearB) ParsecC) BarnD) Astronomical Unit

Answer

✓ Correct Answer: Option C

Explanation: Solution: A Barn is a specific measurement unit of Area ($10^{-28}m^2$), often leveraged in cross-sectional nuclear physics. Light year, Parsec, and Astronomical Unit (AU) map geometric spatial distances.

Question 8

8. A motor is rated at 10\text; Horsepower (hp)}. Approximately how many Watts (W) is this?

A) 74.6 WB) 7460 WC) 1000 WD) 550 W

Answer

✓ Correct Answer: Option B

Explanation: Solution: 1 horsepower (hp) \approx 746 Watts. Thus, $10 hp = 10 \times 746 = 7460 W$.

Question 9

9. The prefix 'Giga' represents which multiplier?

A) $10^{3}$B) $10^{6}$C) $10^{-9}$D) $10^{9}$

Answer

✓ Correct Answer: Option D

Explanation: Solution: In the metric system factor indices: <ul> <li>Kilo = $10^3$</li> <li>Mega = $10^6$</li> <li>Giga = $10^9$</li> <li>Tera = $10^{12}$</li> </ul>

Question 10

10. What is the SI unit of thermodynamic temperature?

A) KelvinB) CelsiusC) FahrenheitD) Rankine

Answer

✓ Correct Answer: Option A

Explanation: Solution: The standard SI base reference unit for absolute system temperature is the Kelvin (K).

Question 11

11. A signal frequency is given as 500 MHz. This value in Hertz (Hz) is:

A) $500 \times 10^3 Hz$B) $500 \times 10^4 Hz$C) $500 \times 10^6 Hz$D) $500 \times 10^9 Hz$

Answer

✓ Correct Answer: Option C

Explanation: Solution: The prefix 'Mega' (M) denotes structural factor $10^6$. Therefore, $500 MHz = 500 \times 10^6 Hz$.

Question 12

12. Which of the following is a supplementary unit in SI?

A) MeterB) RadianC) AmpereD) Mole

Answer

✓ Correct Answer: Option B

Explanation: Solution: The standard SI architecture structures Radian (plane structural angle) and Steradian (solid angle calculations) as supplementary metrics.

Question 13

13. The unit of surface tension in SI system is:

A) N \cdot mB) $N \cdot m^2$C) N/mD) $N/m^2$

Answer

✓ Correct Answer: Option C

Explanation: Solution: Surface tension (T) acts as dimensional Force (F) exerted across cross length lines (l). $$T = \frac{F}{l}$$ Hence, the unit tracks directly as Newton per meter (N/m).

Question 14

14. 1 unified atomic mass unit (u) is approximately equal to:

A) $1.66 \times 10^{-27}kg$B) $1.66 \times 10^{-24}kg$C) $9.1 \times 10^{-31}kg$D) $6.02 \times 10^{23}kg$

Answer

✓ Correct Answer: Option A

Explanation: Solution: 1 u equals $\frac{1}{12}$ the mass of a rest carbon-12 nucleus, scaling around $1.66 \times 10^{-27}kg$.

Question 15

15. Which of these is the SI unit for the amount of substance?

A) GramB) KilogramC) Cubic meterD) Mole

Answer

✓ Correct Answer: Option D

Explanation: Solution: The foundational metric base unit for aggregate chemical element counts is the Mole (mol).

Question 16

16. How many meters are there in 1 nanometer (nm)?

A) $10^{-6}m$B) $10^{-9}m$C) $10^{-12}m$D) $10^{-3}m$

Answer

✓ Correct Answer: Option B

Explanation: Solution: The micro prefix 'nano' scales factor variables down to $10^{-9}$. Thus, $1 nm = 10^{-9}m$.

Question 17

17. If a car covers a distance of 100 meters in 5 seconds, its average speed in SI units is:

A) 20 m/sB) 500 m/sC) 0.05 m/sD) 20 km/h

Answer

✓ Correct Answer: Option A

Explanation: Solution: $$Speed = \frac{Distance}{Time} = \frac{100m}{5 s} = 20m/s$$

Question 18

18. Which of the following units is used for measuring electric resistance?

A) VoltB) AmpereC) OhmD) Farad

Answer

✓ Correct Answer: Option C

Explanation: Solution: Electrical pathway resistance is sized in Ohm metrics (\Omega).

Question 19

19. 1 Joule is equivalent to:

A) $1 N \cdot m^2$B) 1 N \cdot mC) 1 N/mD) 1kg \cdot m/s

Answer

✓ Correct Answer: Option B

Explanation: Solution: Work Evaluated = Force $\times$ Displacement. Therefore, $1 Joule = 1 Newton \times 1 meter = 1 N \cdot m$.

Question 20

20. The SI unit of power is the Watt. 1 Watt is equal to:

A) 1 Joule \cdot secondsB) 1 Newton/secondC) $1kg \cdot m^2/s^2$D) 1 Joule/second

Answer

✓ Correct Answer: Option D

Explanation: Solution: Power evaluates work run speed variations (P = W/t). Thus, 1 Watt = 1 Joule / 1seconds.

Accepted Answer

✓ Correct Answer: Option B

Explanation: Solution: The SI unit for a plane angle is the radian, whereas the SI unit for a solid angle is the Steradian (symbol: sr).

Grade 11 : Physics - Units (Set 1)

1. In the International System of Units (SI), which unit is used to measure the luminous intensity of a light source?

2. A researcher is calculating the angle subtended by a spherical surface at its center. What is the SI unit for this 'solid angle'?

3. Which of the following is considered a 'Fundamental Unit' in the SI system?

4. A high-speed train travels at a velocity of 180 km/h. What is its speed expressed in the SI unit of velocity (m/s)?

5. The pressure exerted by a fluid is measured in Pascals (Pa). Which of the following represents 1 Pascal in terms of base units?

6. An atomic physicist measures the radius of a nucleus to be 1 Angstrom (Å). This length is equivalent to:

7. Which of the following is NOT a unit of distance?

8. A motor is rated at 10\text; Horsepower (hp)}. Approximately how many Watts (W) is this?

9. The prefix 'Giga' represents which multiplier?

10. What is the SI unit of thermodynamic temperature?

11. A signal frequency is given as 500 MHz. This value in Hertz (Hz) is:

12. Which of the following is a supplementary unit in SI?

13. The unit of surface tension in SI system is:

14. 1 unified atomic mass unit (u) is approximately equal to:

15. Which of these is the SI unit for the amount of substance?

16. How many meters are there in 1 nanometer (nm)?

17. If a car covers a distance of 100 meters in 5 seconds, its average speed in SI units is:

18. Which of the following units is used for measuring electric resistance?

19. 1 Joule is equivalent to:

20. The SI unit of power is the Watt. 1 Watt is equal to: