# Chapter-wise important notes science (Physics) for Board Exams The best way to escape the exam fear is “Practice“. Practice all the questions given below for physics will you solve all the questions that will appear in CBSE Board Exam of Science.

Chapter-wise most important science (Biology) questions for Board Exam

## Light: Reflection and Refraction

1. Refractive indices of medium A, B and C are 1.3, 1.5 and 1.4 respectively. In which of the following the speed of light will be the :
(a) fastest ?
(b) slowest ?
2. A compound lens is made up of two thin lenses having power + 12.5 D and – 2.5 D. Find the focal length and power of the combination.
3. Light enters from air to kerosene having a refractive index of 1.47. What is the speed of light in kerosene ?
4. A 5 cm tall object is placed perpendicular to principal axis of a convex lens of focal length 10 cm. If the object is placed 30 cm away from the lens, find the position, size and nature of image.

Short Notes on Light: Reflection

5. One half of a convex lens is covered with black paper.
(a) Show the formation of image of a object placed at 2F, of such covered lens with the help of ray diagram. Mention the position and nature of the image.
(b) Draw the ray diagram for same object at same position in front of the same lens, but now uncovered. Will there be any difference in
image obtained in the two cases ? Give reasons for your answers.
6. A thin converging lens forms a (i) real magnified image, (ii) virtual magnified image.
(a) Write the position of object in each case.
(b) Draw labelled diagram for each case.
7. (a) What happens to a ray of light when it travels from one medium to another having equal refractive indices ?
(b) State the cause of refraction of light.
8. (a) Define 1 dioptre of power. Find the focal length of a lens of power – 2.0 D.
(b) Why does a lemon kept in water in a glass tumbler appear to be bigger than actual size ?

Want to analyse your preparation Level? Here is a Quiz on Reflection of Light!

9. A ray travelling in water enters obliquely into glass. Does the light bend towards or away from the normal and why ?
10. An object is placed at the focus of a convex lens. Draw ray diagram to locate the position of image formed.

## Human Eye and Colourful World

1. Which of the two is scattered more easily – light of shorter wavelength or light of longer wavelength ?
2. What is the near and far point of a normal eye ?
3. State two effects produced by the scattering of light by the atmosphere.
4. What is tyndall effect ?
5. Which light has longer wavelength – red light or blue light ?
6. What do you understand by dispersion of light ?
7. As light rays pass from air into a glass prism, are they refracted towards or away from the normal ?

1. Why do stars twinkle at night ?
2. Describe the formation of rainbow in the sky with the help of a diagram.
3. Why the sun appear red while sunset and sunrise ? Explain.
4. Why do stars seem higher than they actually are ? Illustrate your answer with the help of a diagram.

1. What is atmospheric refraction ? What causes atmospheric refraction ?
2. Draw a neat and labelled diagram of the experimental set-up for observing the scattering of light in a colloidal solution of sulphur to show how the sky appears blue and the sun appears red at sunrise and sunset.

## Electricity

Short Notes & Video Lectures : Electricity

VERY SHORT ANSWER TYPE QUESTIONS (1 Mark)

1. Define S.I. unit of :
(a) Electric current
(b) Potential difference
(c) Resistance
(d) Electric power
(e) Electrical energy consumed
2. Define the term resistivity.
3. Device used for measuring the current is……………. .
4. Name the element of filament of a bulb.
5. Write two types of resistors combination.

SHORT ANSWER TYPE QUESTIONS (2 Marks)

1. How the voltmeter and ammeter are connected in a circuit ?
2. Why the filament of bulb has high melting point ?
3. How does fuse wire protect electrical appliances ?
4. Find the number of joules in 1 KWh.
5. Find a relationship between P, I and V.
6. On what factors does resistance of a conductor depend ?

SHORT ANSWER TYPE QUESTIONS (3 Marks)

1. State Ohm’s law. Derive relation between I, V and R. Draw the graph between V and I.
2. What is Joule’s heating effect of current P ? Derive its expression.
3. What would be new resistance if length of conductor is doubled and thickness is halved ?
4. Find the effective resistance between A and B. 5. Which is the better way to connect lights and other appliances in domestic wiring and why ?

LONG ANSWER TYPE QUESTIONS (5 Marks)

1. Explain the Joule’s law of heating. How and on what factors does the heat produced
in a conductor depends ?
2. In the circuit given below, calculate : (a) Total effective resistance.
(b) Potential difference across 4Ω, 2Ω.
3. Three resistances of 2Ω, 3Ω and 5Ω are connected in electric circuit. Find :
(a) maximum effective resistance.
(b) minimum effective resistance.
4. On what factors, the resistance of a conductor depends ? Give the mathematical expression. Give the SI unit of resistivity.

## Magnetic Effect of Electric Current

VERY SHORT ANSWER TYPE QUESTIONS (1 Mark)

1. Define magnetic field lines.
2. What is the frequency of a.c. in India ?
3. Who discovered the electromagnetic induction ?
4. What is short circuit ?
5. Why does two magnetic field lines not intersect ?

SHORT ANSWER TYPE QUESTIONS (2 Marks)

1. A charged particle enters at right angle into a uniform magnetic field. What is the nature of charge particle if it experiences a force in a direction pointing vertically out of page.
2. When does short circuit occur ?
3. Write the three ways to produce magnetic field.
5. Write the use of safety device used in electric circuit.

SHORT ANSWER TYPE QUESTIONS (3 Marks)

1. What is solenoid ? Where the magnetic field is uniform in solenoid ?
2. Draw the pattern of magnetic field lines due to current carrying straight conductor.
3. What is earth wire ? How it works in our domestic circuit ?

LONG ANSWER TYPE QUESTIONS (5 Marks)

1. What is electromagnetic induction ? Explain with an activity. Write its one application.
2. Draw the schematic diagram of domestic circuit. Write the colour and nature of neutral wire, live wire and earth wire.
3. What is an electromagnet ? What material are used to make electromagnet ? Can we use steel to make electromagnet ?

Chapter-wise most important science questions for Board Exams

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