Bihar Board Class 10 Physics Notes 2025 | Complete Revision with Important Objective Questions

Physics is one of the most important subjects for Bihar Board Class 10 students. It deals with the study of matter, energy, force, and their interactions. A good understanding of physics not only helps you score well in board exams but also builds a foundation for higher studies in science.

Bihar Board Class 10 Physics Notes 2025
Bihar Board Class 10 Physics Notes 2025

In this article, we will provide chapter-wise detailed notes for Bihar Board Class 10 Physics including formulas, important definitions, examples, and key concepts to make your revision easier.

Table of Contents

Bihar Board Class 10 Physics Notes 2025 | Complete Revision with Important Objective Questions

Chapter 1: Light – Reflection and Refraction

Reflection of Light

  • The bouncing back of light rays from a polished surface is called reflection.

  • Laws of Reflection:

    1. Angle of incidence = Angle of reflection

    2. Incident ray, reflected ray, and normal lie in the same plane

Mirror Formula (Concave Mirror):

1f=1v+1u\frac{1}{f} = \frac{1}{v} + \frac{1}{u}

Where:

  • f = focal length

  • v = image distance

  • u = object distance

Magnification (M):

M=hiho=vuM = \frac{h_i}{h_o} = \frac{v}{u}

Example: If an object is placed 30 cm in front of a concave mirror with focal length 15 cm, find the image position.

Solution:

1f=1v+1u⇒115=1v+1−30\frac{1}{f} = \frac{1}{v} + \frac{1}{u} \quad \Rightarrow \quad \frac{1}{15} = \frac{1}{v} + \frac{1}{-30} 1v=115+130=1+0.515=1.515=110\frac{1}{v} = \frac{1}{15} + \frac{1}{30} = \frac{1+0.5}{15} = \frac{1.5}{15} = \frac{1}{10}

So, v = 10 cm.

Refraction of Light

  • The bending of light when it passes from one medium to another is called refraction.

Laws of Refraction (Snell’s Law):

sin⁡isin⁡r=n21\frac{\sin i}{\sin r} = n_{21}

Where:

  • i = angle of incidence

  • r = angle of refraction

  • n21n_{21} = refractive index of medium 2 with respect to medium 1

Lens Formula:

1f=1v−1u\frac{1}{f} = \frac{1}{v} – \frac{1}{u}

Magnification by Lens:

M=hiho=vuM = \frac{h_i}{h_o} = \frac{v}{u}

Chapter 2: The Human Eye and the Colourful World

Structure of Human Eye

  • Cornea: Refracts light

  • Lens: Forms image on retina

  • Retina: Contains rods and cones, converts light into electrical signals

  • Ciliary Muscles: Adjust lens curvature

Power of Accommodation: Ability of the eye to focus both near and distant objects.

Defects of Vision:

  • Myopia (Short-sightedness) → Corrected by concave lens

  • Hypermetropia (Long-sightedness) → Corrected by convex lens

  • Presbyopia → Due to old age

Chapter 3: Electricity

Ohm’s Law

V=IRV = IR

Where:

  • V = Potential difference

  • I = Current

  • R = Resistance

Resistance in Series:

R=R1+R2+R3R = R_1 + R_2 + R_3

Resistance in Parallel:

1R=1R1+1R2+1R3\frac{1}{R} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3}

Electric Power:

P=VI=I2R=V2RP = VI = I^2R = \frac{V^2}{R}

Example: A bulb of resistance 10 Ω is connected to 5 A current. Find power consumed.

P=I2R=25×10=250 WP = I^2R = 25 \times 10 = 250 \, W

Chapter 4: Magnetic Effects of Electric Current

Magnetic Field

  • Region around a magnet where magnetic force can be experienced.

Right-Hand Thumb Rule:
If current flows through a conductor, then the thumb of the right hand gives direction of current and curled fingers show direction of magnetic field.

Electromagnetism: Current-carrying coil behaves like a magnet.

Fleming’s Left Hand Rule: Used to find direction of force on current-carrying conductor in magnetic field.

Electric Motor: Device that converts electrical energy into mechanical energy.

Electric Generator: Device that converts mechanical energy into electrical energy.

Chapter 5: Sources of Energy

Bihar Board Class 10 Physics Notes 2025
Bihar Board Class 10 Physics Notes 2025

Conventional Sources of Energy

  • Coal, petroleum, natural gas

  • Cause pollution and are non-renewable

Non-Conventional Sources of Energy

  • Solar energy, wind energy, hydroelectric power, geothermal energy

  • Renewable and eco-friendly

Solar Panel Formula (Efficiency):

η=Useful Energy OutputTotal Energy Input×100\eta = \frac{\text{Useful Energy Output}}{\text{Total Energy Input}} \times 100

Chapter 6: Our Environment

  • Biodegradable Waste: Can be decomposed by microorganisms

  • Non-Biodegradable Waste: Cannot be decomposed easily

  • Energy flow in ecosystem follows 10% law – only 10% of energy is transferred from one trophic level to the next.

Chapter 7: Sustainable Management of Natural Resources

  • Forest and Wildlife Conservation

  • Water Harvesting

  • Reduce, Reuse, Recycle principle (3Rs)

  • Sustainable development ensures resources for future generations

Final Revision Tips

  • Memorize all formulas with proper units.

  • Practice numerical problems regularly.

  • Draw neat and labeled diagrams for mirrors, lenses, electric circuits, and human eye.

  • Revise definitions and laws as they are frequently asked in exams.

    Bihar Board Class 10 Physics – 20 Important Objective Questions

    Chapter 1: Light – Reflection and Refraction

    Q1. The mirror used in car headlights is:

    a) Convex mirror
    b) Concave mirror
    c) Plane mirror
    d) None

    Answer: Concave mirror (b).

    Q2. SI unit of focal length is:

    a) Dioptre
    b) Metre
    c) Centimetre
    d) Watt

    Answer: Metre (b).

    Q3. Splitting of white light into seven colours is called:

    a) Reflection
    b) Refraction
    c) Dispersion
    d) Diffraction

    Answer: Dispersion (c).

    Q4. Which lens is used to correct Hypermetropia?

    a) Convex lens
    b) Concave lens
    c) Plano-concave lens
    d) Cylindrical lens

    Answer: Convex lens (a).

    Q5. Mirror formula is:

    a) 1f=1u−1v\frac{1}{f} = \frac{1}{u} – \frac{1}{v}
    b) 1f=1v+1u\frac{1}{f} = \frac{1}{v} + \frac{1}{u}
    c) 1f=1v−1u\frac{1}{f} = \frac{1}{v} – \frac{1}{u}
    d) 1f=1u+1h\frac{1}{f} = \frac{1}{u} + \frac{1}{h}

    Answer: 1f=1v+1u\frac{1}{f} = \frac{1}{v} + \frac{1}{u} (b).

    Chapter 2: The Human Eye and the Colourful World

    Q6. The part of the eye that controls the amount of light entering is:

    a) Cornea
    b) Lens
    c) Iris
    d) Retina

    Answer: Iris (c).

    Q7. The near point of a normal human eye is:

    a) 10 cm
    b) 25 cm
    c) 50 cm
    d) Infinity

    Answer: 25 cm (b).

    Q8. Twinkling of stars is due to:

    a) Reflection
    b) Refraction
    c) Dispersion
    d) Diffraction

    Answer: Refraction (b).

    Q9. The defect of vision corrected by concave lens is:

    a) Myopia
    b) Hypermetropia
    c) Presbyopia
    d) Astigmatism

    Answer: Myopia (a).

    Q10. The real and inverted image in human eye is formed on:

    a) Iris
    b) Lens
    c) Cornea
    d) Retina

    Answer: Retina (d).

    Chapter 3: Electricity

    Bihar Board Class 10 Physics Notes 2025
    Bihar Board Class 10 Physics Notes 2025

    Q11. SI unit of electric current is:

    a) Ohm
    b) Ampere
    c) Volt
    d) Coulomb

    Answer: Ampere (b).

    Q12. SI unit of resistance is:

    a) Joule
    b) Coulomb
    c) Ohm
    d) Watt

    Answer: Ohm (c).

    Q13. Formula of electric power is:

    a) P=VIP = VI
    b) P=IRP = IR
    c) P=VIP = \frac{V}{I}
    d) P=RIP = \frac{R}{I}

    Answer: P=VIP = VI (a).

    Q14. In parallel connection, the equivalent resistance is:

    a) More than the largest resistance
    b) Less than the smallest resistance
    c) Equal to the average resistance
    d) Zero

    Answer: Less than the smallest resistance (b).

    Q15. Work done in moving 1 coulomb charge across 1 volt is:

    a) 1 Joule
    b) 1 Watt
    c) 1 Ampere
    d) 1 Ohm

    Answer: 1 Joule (a).

    Chapter 4: Magnetic Effects of Current

    Q16. The rule to find the direction of magnetic field around a conductor is:

    a) Fleming’s Left-Hand Rule
    b) Fleming’s Right-Hand Rule
    c) Right-Hand Thumb Rule
    d) Joule’s Law

    Answer: Right-Hand Thumb Rule (c).

    Q17. A device that converts electrical energy into mechanical energy is:

    a) Generator
    b) Motor
    c) Cell
    d) Transformer

    Answer: Motor (b).

    Q18. A device that converts mechanical energy into electrical energy is:

    a) Motor
    b) Generator
    c) Battery
    d) Transformer

    Answer: Generator (b).

    Q19. The rule used to find the direction of force on a current-carrying conductor in a magnetic field is:

    a) Fleming’s Left-Hand Rule
    b) Fleming’s Right-Hand Rule
    c) Joule’s Law
    d) Newton’s Law

    Answer: Fleming’s Left-Hand Rule (a).

    Q20. Electromagnetism was discovered by:

    a) Faraday
    b) Newton
    c) Oersted
    d) Joule

    Answer: Oersted (c).

     Conclusion

    Physics is a very scoring subject in Bihar Board Class 10 if you prepare it with the right strategy. The above 20 important objective questions with options cover all the major chapters — Light, Human Eye, Electricity, Magnetism, and Energy concepts. These questions are frequently asked in board exams, so practicing them will not only strengthen your conceptual clarity but also improve your speed in the objective section.

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