π¦ Section A: Short Questions (Physics)
(1) How does physics play an important role in our life?
Physics explains how nature works and helps in the development of machines, transport, energy, and medical equipment, improving our daily life.
(2) Estimate your age in minutes and seconds.
If age is 15 years:
- Minutes = 15 Γ 365 Γ 24 Γ 60 = 7,884,000 minutes
- Seconds = 7,884,000 Γ 60 = 473,040,000 seconds
(3) Which base quantities are involved in force, pressure, and charge?
- Force: Mass, Length, Time
- Pressure: Mass, Length, Time
- Charge: Current, Time
(4) Show that prefix micro is thousand times smaller than milli.
- Milli = 10β310^{-3}10β3
- Micro = 10β610^{-6}10β6
10β610β3=10β3=11000\frac{10^{-6}}{10^{-3}} = 10^{-3} = \frac{1}{1000}10β310β6β=10β3=10001β
So, micro is 1000 times smaller than milli.
(5) Justify that displacement is a vector and energy is scalar.
Displacement has both direction and magnitude, so it’s a vector. Energy has only magnitude, no direction, so it is scalar.
(6) Why is screw gauge more precise than vernier caliper?
Because screw gauge has a smaller least count (0.01 mm), it can measure smaller objects more accurately than vernier caliper (0.1 mm).
(7) Differentiate between mechanical and digital stopwatch.
- Mechanical stopwatch: Has a needle and works with springs.
- Digital stopwatch: Shows time on screen, runs on battery, and gives more accurate readings.
(8) How is a measuring cylinder used to measure the volume of an irregular-shaped stone?
Fill the cylinder with water, note the initial volume. Drop the stone and note the new volume. The difference gives the stone’s volume.
(9) Precautions while using a measuring cylinder?
- Place on a flat surface.
- Read at eye level.
- Avoid splashing.
- Use correct units.
(10) Why consider significant digits in measurement?
Significant digits reflect the precision of a measurement and help avoid false accuracy in calculations.
(11) How can random errors be reduced?
By repeating the experiment multiple times and taking the average value.
(12) Differentiate between precision and accuracy.
- Precision: Repeated measurements give similar results.
- Accuracy: Measurement is close to the actual or true value.
π¨ Section B: Long Questions (Physics)
(1) Define physics. Describe its revolutionary role in technology.
Physics is the study of matter, energy, and their interactions. It explains natural laws and helps in technological advancement. For example, electricity generation, mobile phones, satellite communication, and medical imaging (like X-rays) all depend on physics. Physics forms the foundation for innovations in engineering, space exploration, and everyday appliances.
(2) List different branches of physics.
- Mechanics
- Thermodynamics
- Electromagnetism
- Optics
- Nuclear Physics
- Quantum Physics
- Solid State Physics
- Astrophysics
Each branch deals with a specific part of the physical world, from motion and heat to atomic particles and celestial bodies.
(3) What are physical quantities? Distinguish between base and derived quantities with examples.
Physical quantities are measurable properties of matter like length, mass, and time.
- Base quantities: Cannot be broken down. (e.g., mass, time, length)
- Derived quantities: Made by combining base quantities. (e.g., speed = distance/time, force = mass Γ acceleration)
Examples:
- Speed = length / time
- Force = mass Γ acceleration
- Pressure = force / area
(4) Differentiate between base quantities and derived quantities.
| Base Quantities | Derived Quantities |
|---|---|
| Fundamental | Formed from base quantities |
| 7 in total | Unlimited |
| Examples: mass, time | Examples: force, area, speed |
(5) What do you mean by unit of physical quantities? Define base and derived units.
A unit is a standard quantity used to measure physical quantities.
- Base units: Units of base quantities (e.g., meter, kilogram, second)
- Derived units: Formed using base units (e.g., m/s for speed, N for force)
(6) What are prefixes? What is their use in measurement?
Prefixes are symbols added before units to represent very large or small values.
They make measurements simpler.
Examples:
- Kilo (k) = 10310^3103
- Milli (m) = 10β310^{-3}10β3
- Micro (ΞΌ) = 10β610^{-6}10β6
(7) What is scientific notation and standard form of measurement? Give examples.
Scientific notation expresses large or small numbers using powers of 10.
Standard form is a number between 1 and 10 multiplied by 10βΏ.
Examples:
- 1000 = 1Γ1031 Γ 10^31Γ103
- 0.0005 = 5Γ10β45 Γ 10^{-4}5Γ10β4
- 50,000 = 5Γ1045 Γ 10^45Γ104
(8) Describe construction and working of vernier calliper.
Construction: It has a main scale and a sliding vernier scale with jaws to hold the object.
Working:
- Place the object between jaws
- Read the main scale
- Note the vernier division that matches
- Add the readings to get the final measurement
Vernier calipers measure internal, external diameters and depth accurately.
(9) What is screw gauge? Define pitch and least count. How is it used to measure the thickness of thin wire?
Screw gauge measures small lengths with high precision.
- Pitch: Distance moved in one rotation
- Least count = Pitch / number of divisions
To measure wire: - Place wire between jaws
- Rotate thimble until it touches wire
- Add main scale and circular scale readings
(10) Define error. Differentiate random and systematic error. How can they be reduced?
Error is the difference between the measured and actual value.
- Random error: Caused by unknown factors; reduced by repeating and averaging.
- Systematic error: Due to faulty instruments; reduced by calibration and proper setup.
(11) Differentiate scalar and vector quantities. Justify examples.
- Scalar: Only magnitude (e.g., distance, speed, mass, energy)
- Vector: Magnitude + direction (e.g., displacement, velocity, force, acceleration)
Displacement shows direction and path, so itβs vector; distance doesnβt, so scalar.
(12) Justify the use of measuring cylinder for volume of liquid.
Measuring cylinders are marked with volume graduations. To measure liquid:
- Pour liquid
- Place cylinder on flat surface
- Read the bottom of the meniscus at eye level
It gives accurate and easy volume readings for liquids.
(13) Differentiate between precision and accuracy.
| Precision | Accuracy |
|---|---|
| Repeated results are consistent | Results are close to actual value |
| Doesnβt guarantee correctness | Measures correctness |
| High precision β High accuracy | High accuracy β High precision |
