Physics MCQs (PYQs) on Units and Measurements (Set 1)

1. Home
2. General Science
3. Physics
4. Units and Measurements
5. MCQs (set 1)

Practice Tip: Select any option to check your answer. Green indicates correct, Red indicates incorrect. Every wrong guess is a step closer to the right one. Keep exploring until you find the right answer to learn from your mistakes.

Test Your Knowledge with MCQs & PYQs

1.

Which of the following is the SI unit of velocity ? (SSC GD Constable PYQ)

• A.kg/m
• B.kg/s
• C.m/s
• D.s/m

Answer: Option C

---

Explanation:
The rate of change of displacement with time is called velocity.
$\mathrm{Velocity}=\frac{\mathrm{displacement}}{\mathrm{time}}$
The SI unit of displacement is meter (m).
The SI unit of time is second (s).
So $\mathrm{Velocity}=\frac{\mathrm{displacement\; (m)}}{\mathrm{time\; (s)}}$
So SI unit of velocity is m/s or m s^-1.
Additional useful information:
→ The dimensional formula of velocity is [M⁰L¹T^-1] or [LT^-1].

2.

What is the formula for density ?(RRB NTPC PYQ)

• A.Density = Mass × Volume
• B.Density = Weight / Volume
• C.Density = Mass / Volume
• D.Density = Volume / Mass

Answer: Option C

---

Explanation:
Density is defined as the mass of a substance per unit volume.
Density = Mass / Volume
Additional useful information:
→ The SI unit of mass density is kg/m³ or kg m^-3.
→ The dimensional formula of mass density is [M¹L^-3T⁰].

3.

What is the SI unit of Power ?(SSC CGL PYQ)

• A.Boyle
• B.Watt
• C.Newton
• D.Pascal

Answer: Option B

---

Explanation:
The rate of doing work or the rate of transfer of energy is called power.
$\mathrm{Power}=\frac{\mathrm{Work}}{\mathrm{Time}}$
The SI unit of work is joule (J).
The SI unit of time is second (s).
So, $\mathrm{Power}=\frac{\mathrm{Work\; (J)}}{\mathrm{Time\; (s)}}$
So, the SI unit of power is J/s, which is called watt (W).
Additional useful information:
→ 1 watt = 1 joule/second.
→ The dimensional formula of power is [M¹L²T^-3].

4.

The relation between Newton and Dyne is given by:(JKSSB JE PYQ)

• A.One Newton = 10³ Dyne
• B.One Newton = 10⁵ Dyne
• C.One Newton = 10⁴ Dyne
• D.One Newton = 10⁶ Dyne

Answer: Option B

---

Explanation:
The SI unit of force is newton (N).
The CGS unit of force is dyne.
The correct relation between newton and dyne is given by:
One newton (N) = 10⁵ dyne
Additional useful information:
→ The dimensional formula of force is [M¹L¹T^-2].

5.

The density of fresh water is _______ the density of salt water.(RRB ALP PYQ)

• A.more than
• B.less than
• C.equal to
• D.negligible compared with

Answer: Option B

---

Explanation:
$\mathrm{Density}=\frac{\mathrm{mass}}{\mathrm{volume}}$
Pure fresh water has a density of approximately 1000 kg/m³. Salt water contains dissolved salts (like sodium chloride) which add extra mass to the liquid while keeping the total volume nearly constant. Because of this added mass, salt water is denser than fresh water. Therefore, the density of fresh water is less than that of salt water.
Additional useful information:
→ The SI unit of mass density is kg/m³.
→ The value of density of water at 4 °C (or 277 K) is 1 g/cm³ or 1000 kg/m³.
→ The density of water is maximum at 4 °C (or 277 K).
→ The dimensional formula of mass density is [M¹L^-3T⁰].

---

• 1

---

Page code: p8