Class 11 Physics Numericals for Beginners – 20 Solved Questions Step by Step
Understand Physics formulas with 20 easy numerical questions, clear calculations, SI units, practical examples and simple explanations for Class 11 students.
Class 11 Physics becomes difficult for many students because the subject is quite different from Class 10 Science. Suddenly, there are more formulas, vectors, motion graphs, forces and calculations. Even students who understand the theory often get confused when a numerical question appears.
You may know the formula for acceleration, but when a question gives initial velocity, time and final velocity together, choosing the correct method becomes confusing. Sometimes the formula is correct but the final answer is wrong because kilometres were not converted into metres or the unit was forgotten.
That is why practising Physics numericals from the basic level is important. Instead of memorising every solved example, students should learn how to identify the given values, choose a formula and solve the question carefully.
This guide includes 20 Class 11 Physics numericals for beginners from different chapters. Every question follows a simple process so you can understand the calculation without feeling lost.
If a chapter itself feels difficult, understand the concept before solving its questions. You can explore the best YouTube channels for Class 11 Physics for lectures that explain motion, forces, energy and numerical-solving methods.
How to Solve Class 11 Physics Numericals Easily
Before starting the solved questions, remember one simple thing: Physics numericals are easier when you solve them in a fixed order.
Suppose a car travels 100 metres in 20 seconds. You need to calculate its average speed. First identify distance and time, then use the speed formula.
This is the same basic method that we will use throughout the following questions.
Common SI Units Used in Physics
| Quantity | SI Unit | Symbol |
|---|---|---|
| Length | metre | m |
| Mass | kilogram | kg |
| Time | second | s |
| Speed | metre per second | m/s |
| Acceleration | metre per second squared | m/s² |
| Force | newton | N |
| Work and Energy | joule | J |
| Power | watt | W |
| Pressure | pascal | Pa |
| Frequency | hertz | Hz |
Class 11 Science students also need regular practice in Maths and Chemistry. If you are arranging free learning resources for all three subjects, the Class 11 subject-wise YouTube study guide can help you organise your study routine.
Units and Measurements – Solved Numericals (1–2)
Units and Measurements is a useful starting chapter because every numerical in Physics depends on correct units. Learn conversions and dimensions before moving towards longer calculations.
Question 1: Convert km/h into m/s
Formula:
- Write the given speed: 90 km/h.
- Multiply by 5/18 to convert the unit.
- 90 × 5/18 = 25.
Easy explanation: One kilometre equals 1000 metres and one hour equals 3600 seconds. Therefore, multiplying by 1000/3600, or 5/18, converts km/h into m/s.
Question 2: Find the Dimensional Formula of Force
Formula:
- Dimension of mass = [M].
- Dimension of acceleration = [LT⁻²].
- Multiply the dimensions of mass and acceleration.
This shows that the dimensions of force contain one power of mass, one power of length and minus two powers of time.
Motion in a Straight Line and Plane – Numericals (3–9)
Motion is one of the most useful chapters for learning Physics calculations. The questions usually involve speed, velocity, acceleration, distance, displacement and time.
Always check whether a question asks for distance or displacement. Distance measures the total path travelled, while displacement depends on the change in position and direction.
Question 3: Calculate Average Speed
- Write the distance as 600 m.
- Write the time as 120 s.
- Divide 600 by 120.
Question 4: Calculate Average Velocity
First move east, then return part of the distance west. East is taken as the positive direction.
- Calculate net displacement: 80 − 30 = 50 m east.
- Use average velocity = displacement / time.
- Substitute: 50/25 = 2.
Remember: The total distance is 110 m, but displacement is only 50 m east. This is why average speed and average velocity are different.
Question 5: Final Velocity and Displacement
Part A: Final Velocity
- Substitute the values: v = 3 + (2 × 5).
- Calculate: v = 3 + 10.
- Final velocity = 13 m/s.
Part B: Displacement
- s = (3 × 5) + ½ × 2 × 5².
- s = 15 + 25.
- Displacement = 40 m.
Question 6: Braking Distance of a Car
Step 1: Find stopping time.
Step 2: Find stopping distance.
Common mistake: Deceleration is negative when the positive direction is the initial direction of motion.
Question 7: Velocity-Time Graph Numerical
Part A: Acceleration
Part B: Displacement
For uniform acceleration, displacement equals average velocity multiplied by time. It is also the area under the velocity-time graph.
Question 8: Resultant of Two Perpendicular Forces
Because the forces are perpendicular, we can use Pythagoras' theorem.
- Square the first force: 6² = 36.
- Square the second force: 8² = 64.
- Add: 36 + 64 = 100.
- Find √100 = 10.
This result gives the magnitude. The resultant direction lies between east and north.
Question 9: Projectile Motion
Step 1: Vertical component.
Step 2: Time of flight.
Step 3: Maximum height.
Step 4: Horizontal range.
The horizontal component is uₓ = 20 cos 30° ≈ 17.32 m/s.
Remember: For a projectile launched and landing at the same height, the total time of flight is twice the time taken to reach the highest point.
Motion and forces form an important foundation for students planning engineering entrance preparation. Once these basics are clear, our JEE Mechanics learning guide can help you move towards more detailed problems in Kinematics, Newton's Laws and Rotation.
Laws of Motion – Solved Numericals (10–12)
Newton's laws explain how forces affect the motion of objects. In numericals, students usually need to calculate force, friction, momentum or impulse.
Question 10: Calculate Force
- Write the mass: 5 kg.
- Write acceleration: 3 m/s².
- Multiply mass by acceleration.
Concept: Newton's second law relates the net external force on an object to its acceleration.
Question 11: Frictional Force
Illustration: Friction acts opposite to the relative sliding motion.
On a horizontal surface with no other vertical force, the normal reaction is mg.
Common mistake: The coefficient of friction has no unit. Frictional force is measured in newtons.
Question 12: Impulse and Change in Momentum
Formula:
- Find change in velocity: 6 − 2 = 4 m/s.
- Multiply by mass: 0.5 × 4.
An impulse of 2 N·s is equivalent to a momentum change of 2 kg·m/s.
When you start solving more numericals, it helps to maintain a notebook for formulas and common mistakes. The short-notes and revision guide explains how to organise formulas and important concepts without copying entire chapters.
Work, Energy and Power – Numericals (13–15)
Work, Energy and Power is easier to understand when you connect formulas with daily activities. Pushing a box, lifting an object and running a machine are familiar examples of these concepts.
Question 13: Calculate Work Done
Since cos 0° = 1:
Work done is positive because the force and displacement point in the same direction.
Question 14: Kinetic Energy of a Moving Object
- Square the speed: 5² = 25.
- Multiply by mass: 4 × 25 = 100.
- Divide by 2.
Remember: Kinetic energy depends on the square of speed. If speed doubles while mass remains constant, kinetic energy becomes four times as large.
Question 15: Calculate Power
Power tells us how quickly work is done. One watt means one joule per second.
Rotation, Gravitation, Fluids, Heat and Waves (16–20)
Once you understand the earlier formulas, the same step-by-step method can be used in other chapters. Some formulas are new, but the solving process remains familiar.
Question 16: Torque in Rotational Motion
Since the force acts perpendicular to the position vector, sin 90° = 1.
Easy explanation: Torque describes the turning effect of a force. For example, a door is easier to open when you push near the handle instead of near the hinges.
Question 17: Gravity at Twice the Earth's Radius
Outside a spherical Earth, gravitational acceleration varies inversely with the square of the distance from its centre.
- Substitute r = 2R.
- g′ = 10 × (R/2R)².
- g′ = 10 × 1/4.
Important: The distance here is measured from Earth's centre, not from the surface. Twice Earth's radius from the centre means an altitude of one Earth radius.
Question 18: Pressure in a Liquid
- Write the water density as 1000 kg/m³.
- Multiply density, gravity and depth.
- 1000 × 10 × 1.5 = 15000.
The answer represents pressure due to the water column. If absolute pressure is required, atmospheric pressure must also be included.
Question 19: Heat Required to Warm Water
Remember: A temperature change of 10°C has the same numerical value as a temperature change of 10 K. This does not mean their zero points are the same.
Question 20: Speed of a Wave
Frequency tells us how many complete oscillations occur per second. Wavelength is the distance between successive points in the same phase, such as two neighbouring crests.
Students preparing for NEET also need regular Physics practice along with Biology and Chemistry. For a wider preparation routine, see the NEET preparation roadmap and organise numerical practice around the chapters you have actually completed.
Class 11 Physics Numericals – Quick Answer Key
Use this table to revise all 20 numericals. Try to remember the formula before checking the answer.
| Question | Topic | Final Answer |
|---|---|---|
| 1 | Unit Conversion | 25 m/s |
| 2 | Dimensions | [MLT⁻²] |
| 3 | Average Speed | 5 m/s |
| 4 | Average Velocity | 2 m/s East |
| 5 | Uniform Acceleration | 13 m/s, 40 m |
| 6 | Braking | 5 s, 50 m |
| 7 | Velocity-Time | 3 m/s², 32 m |
| 8 | Vectors | 10 N |
| 9 | Projectile Motion | 2 s, 5 m, 34.64 m |
| 10 | Newton's Law | 15 N |
| 11 | Friction | 20 N |
| 12 | Impulse | 2 N·s |
| 13 | Work | 60 J |
| 14 | Kinetic Energy | 50 J |
| 15 | Power | 30 W |
| 16 | Torque | 6 N·m |
| 17 | Gravitation | 2.5 m/s² |
| 18 | Fluid Pressure | 15000 Pa |
| 19 | Heat | 21000 J |
| 20 | Waves | 30 m/s |
Important Class 11 Physics Formulas for Beginners
This formula sheet brings together the main equations used in the solved examples. Learn what the symbols mean and where each formula can be applied.
| Concept | Formula |
|---|---|
| Average Speed | Total distance / Total time |
| Average Velocity | Displacement / Time interval |
| Acceleration | a = (v − u)/t |
| Final Velocity | v = u + at |
| Displacement | s = ut + ½at² |
| Net Force | F = ma |
| Kinetic Friction | fₖ = μₖN |
| Impulse | J = Δp |
| Work by Constant Force | W = Fs cos θ |
| Kinetic Energy | KE = ½mv² |
| Average Power | P = W/t |
| Torque Magnitude | τ = rF sin θ |
| Gravity Outside Earth | g(r) = GM/r² |
| Fluid Gauge Pressure | P = ρgh |
| Heat for Temperature Change | Q = mcΔT |
| Wave Speed | v = fλ |
How to Practise Physics Numericals Without Getting Confused
The easiest way to improve numerical-solving skills is to practise a small number of questions carefully and understand every mistake. Solving many questions without checking the method is not always useful.
1. Understand the Formula Before Memorising It
Learn what the symbols mean and when the formula can be applied. For example, before using F = ma, understand that the force is the net external force responsible for acceleration.
2. Convert Units Before Calculation
A speed given in km/h should be converted to m/s when the rest of the question uses SI units. Similarly, grams may need to be converted into kilograms.
3. Draw Simple Diagrams for Motion and Forces
A small sketch can help you understand the direction of motion, friction or displacement. Make sure the directions are clear before assigning positive and negative signs.
4. Solve the Same Question Without Seeing the Answer
After reading a worked example, close the solution and solve it again. Then change one value and try a similar question on your own.
5. Maintain a Physics Mistake Notebook
Record whether a wrong answer came from a formula mistake, a calculation mistake or an incorrect unit. When you revise, focus on the types of errors that appear repeatedly.
6. Use Focused Practice Sessions
Numerical problems need concentration, especially when several steps are involved. If your study session becomes distracted, follow the techniques in our guide to studying without losing concentration . A focused session with five properly solved numericals is better than a long session of copied solutions.
A Simple 7-Day Physics Numerical Practice Plan
Beginners can use this plan to practise the main concepts gradually. Adjust the number of questions according to your current school syllabus.
Practise SI unit conversion, dimensions and significant figures.
Solve speed, velocity and uniform acceleration questions.
Learn basic components, resultant vectors and projectile motion.
Solve net force, friction and impulse problems.
Practise work done, kinetic energy and power.
Practise basic gravitation, fluid pressure, heat and waves.
Attempt ten mixed questions without referring to formulas. Review wrong answers afterwards.
Return to the formulas and concepts you found difficult. Gradually try more challenging questions.
If you are preparing for entrance examinations along with school studies, our self-study guide for competitive exams explains how to balance concept learning, practice and revision.
Common Mistakes in Class 11 Physics Numericals
- Using the wrong formula: Read what the question asks before choosing an equation.
- Ignoring SI units: Convert values before substitution where required.
- Confusing distance and displacement: Check whether direction matters.
- Forgetting negative signs: Define your positive direction in motion questions.
- Skipping intermediate steps: Show the main substitution so calculations can be checked.
- Forgetting squared values: Check expressions such as v² and t² carefully.
- Mixing up mass and weight: Mass is measured in kg, while weight is a force measured in N.
- Writing answers without units: A final numerical result should include the appropriate unit.
Test Your Understanding – 5 Quick Questions
Try solving these simple variations before opening the answers.
1. A body travels 150 m in 30 s. Find average speed.
Average speed = 150/30 = 5 m/s.
2. A 6 kg body accelerates at 2 m/s². Find the net force.
F = ma = 6 × 2 = 12 N.
3. Find the kinetic energy of a 2 kg body moving at 3 m/s.
KE = ½ × 2 × 3² = 9 J.
4. A machine performs 500 J of work in 10 s. Find average power.
P = 500/10 = 50 W.
5. A wave has frequency 5 Hz and wavelength 4 m. Find its speed.
v = fλ = 5 × 4 = 20 m/s.
Frequently Asked Questions
How do I start solving Class 11 Physics numericals?
Start with easy questions from Units and Measurements and Motion. Write the given values, convert units, choose the formula and solve each step carefully. Check the answer before moving to harder questions.
Which Class 11 Physics chapters have numericals?
Numericals appear across many chapters, including Units and Measurements, Kinematics, Laws of Motion, Work-Energy, Rotational Motion, Gravitation, Fluids, Thermal Physics, Oscillations and Waves.
Is Class 11 Physics difficult for beginners?
Physics may feel difficult initially because students encounter more mathematical concepts. Understanding formulas and practising simple examples regularly can make the subject easier.
How many Physics numericals should I practise daily?
There is no fixed number for everyone. Beginners can start with a small set of questions and focus on correct methods. Increase the number and difficulty as your understanding improves.
Are these 20 numericals official NCERT questions?
No. These are original practice examples based on common Class 11 Physics concepts. Students should also complete their prescribed NCERT textbook exercises and school assignments.
How can I remember Physics formulas?
Learn what each symbol means, practise the formula in different questions, create a small formula sheet and revisit the topic after a gap. Understanding helps you remember which formula is useful in a particular situation.
Conclusion
Class 11 Physics numericals become easier when you learn the method instead of memorising solved answers. Start with simple conversions, speed, velocity and acceleration before moving towards forces, energy and other chapters.
Practise one question at a time, understand why the formula works and always include the correct unit in your final answer. When a calculation goes wrong, check the mistake and try another question based on the same concept.
These 20 solved examples are a useful starting point for beginners. Continue with NCERT examples, textbook exercises and school-level practice to build a stronger understanding of Physics.
Keep your practice regular and focus on understanding each step. With time, even difficult Physics numericals can become much more manageable.
