## Monday, 12 February 2018

### CBSE CLASS10 PHYSICS IMPORTANT QUESTIONS 2017 -2018

CBSE CLASS 10 PHYSICS CHAPYERWISE IMPORTANT QUESTIONS  2017-2018
LIGHT REFLECION AND REFRACTION
ONE MARK QUESTION
1. Refractive index of water is 4/3 and that of the glass is 3/2 with regard to air. What is the refractive index of glass with respect to the water? What is the power of concave lens of focal length 200cm?
2. The radius of curvature of spherical mirror is 20cm.What is its focal length?
3. What is the angle of reflection when a ray of light falls normally on a plane mirror?
4. What is the magnification produced by the plane mirror?
5. What is the nature of image formed by concave mirror if magnification produce by mirror is +3.
6. If the speed of light in a medium id 2 x 108 m/s, then what is refractive index
7. The refractive index of diamond is 2.42. What is the meaning of this statement in relation to the speed of light?
8. What do you mean by Power of the lens?
TWO MARKS QUESTION
9. The power of the lens is -2D .What is the focal length and nature of the lens?
10. An object 2cm high produce areal image 3 cm high , when placed at a distance of 15cm from concave mirror. Calculate the position of the image..
11. The power of a focal length is – 4D.State the nature of lens and any two characteristics of the image formed by the lens.
12. State two examples based on phenomenon of refraction of light in everyday life situation.
13. Distinguish between real and virtual image.
14. Name the type of mirror used in the following situations: a) Headlights of car b) rear – view mirror of vehicles
15. An object is placed at a distance of 10 cm from convex mirror of focal length 15 cm. Find the position and nature of image.
16. Define: 1) Snell’s law of refraction of light. 2) Pole of a concave mirror.
17. (a) we prefer to use a convex mirror as a rear view mirror in vehicles. Why ?
18. State a condition for no refraction of light when light enter from one medium to another.
THREE MARKS QUESTION
19. The refractive indices of alcohol and turpentine oil with respect to air are 1.36 and 1.47 respectively. Find the refractive index of turpentine oil with respect to alcohol. In which of the two media the speed of light will be more.
20. a )Define power of a lens and give its unit. b) A convex lens forms a real and inverted image of needle at a distance of 50cm from it. Where is the needle placed in front of this lens if the size of the image is equal to the size of the object? Also find power of the lens
21. Two thin lenses of focal lengths +20 cm and – 15 cm are kept in contact. What is the focal length and power of the combination?
22. An object 2 cm high is placed at a distance of 16 cm from a concave mirror which produces a real image 3cm high. (a) Find the position of the image (b) What is the focal length of mirror?
23. Using lens formulae, find the position of image, its nature
24. An object is placed at a distance of 10cm in front of convex mirror of focal length 15cm. find the nature and position of image.
25. Draw a ray diagram and show the image formed by a concave mirror when the object is kept at focus.
26. Two thin lenses of power +3.5D and -2.5 D are placed in contact. Find the power & focal length of lens combination ?
27. Define magnification. Write the sign convention used for expressing it. and find magnification formed by a concave lens of focal length 20cm and the object is at 15cm.
28. What is the lens formula? Write the sign convention for various mirror and lens.
29. Name the lens/ mirror in the following situations; i) Rear View mirror ii) magnifying Glass iii) Mirror with Dentist iv) Correction of Myopia
FIVE MARKS QUESTION
30.Draw a ray diagram in each of the following cases to show the formation of an image, when an object is placed (a) Between optical centre and principal focus of a convex lens. b) Between F and 2F of concave lens c) At 2F of convex lens
31. Write the characteristic of image formed in each case.
32. A 1 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20cm.The distance of the object from the lens is 15cm.Find the nature, position, size and magnification of the image.
33. Find the size, nature and position of image formed when an object of size 1 cm is placed at a distance of 15 cm from concave mirror of focal length 10 cm.
34. Draw the ray diagram for the different positions of the images formed by concave mirror.

HUMAN EYE AND COLOURFULL WORLD
ONE MARKS QUESTION
1. What is the far point and near point of the human eye with normal vision?
2. List the three phenomenon of light which is responsible for the formation of the rainbow in sky?
3. Name the place where the image is formed in the eye?
4. Name the muscular diaphragm that controls the size of the pupil.
5. What is the cause of dispersion of light?
6. Give the cause of cataract of eye.
7. Which color has got more wavelengths?
8. What makes bees respond to ultraviolet light?
9. What is the focal length of a plane mirror?
10. Which of the two has a great power, a lens of shot focal length or a lens of large length?
11. What does m= +1 stand for?
12. What is the power of a lens if its focal lenth is 50cm?
13. What is the nature of image at retina?
14. Name the point inside the lens through which a ray of light goes deviated?
15. What is the S.I. unit of power of a lens?
16. Name the photographic film equivalent to our eye .
17. Why does a glass slab not disperse white light?
18. Why do we not perceive the depth of a lake ?
19. Name two causes of Myopia, Hypermetropia and presbiopia.
20. Name the liquids that keep our eye soft.
21. What causes rainbow formation?
22. What is Mirage?
TWO MARKS QUESTION
23. Why are ‘danger’ signal lights red in colour?
24. Give reasons why the planets do not twinkle.
25. What do you mean by far point and near point of eye?
26. What is presbyopia? State the cause of it and how is it corrected?
27. Why does it takes sometimes to see in a dim room when you enter the room from bright sunlight outside.
28. Can we see a rainbow on the moon?
29. Does a beam of light give a spectrum on passing through a hollow prism?
30. What is scattering of light ? Explain with an example .
31. Why planets do not twinkle.
32. What is dispersion? What happens when light is passed through a glass prism.
THREE MARKS QUESTION
33. A person needs a lens of power 4.5 D for correction of her vision.What kind of defect in vision is she suffering from? What is the focal length of the corrective lens?What is the nature of the corrective lens?
34. A person with a myopia eye cannot see objects beyond a distance of 1.5m. What would be the
35. Power of corrective lens? Which type of lens is used?
36. What do you understand by myopia? Write two causes of it?
37. What is hypermetropia? State two causes of hypermetropia with help of ray diagrams to show: The eye defect hypermetropia.
38. What is meant by advance sunrise and delayed sunset ? Draw a labeled diagram to explain these phenomenon.
FIVE MARKS QUESTION
39. Explain myopia and hypermetropia with the help of ray diagrams and show how these defects can be corrected?
40. What is meant by dispersion and recombination? Explain with the help of a diagram? What is a spectrum? Name the various colors of spectrum of white light in proper sequence.
41. what is atmospheric refraction? Use this phenomenon to explain the following natural events. i)Twinkling of stars. ii) advanced sun rise and delayed sun set . Draw a diagrams to illustrate your
ELECTRICITY
ONE MARKS QUESTION
1. Define resistivity of material.
2. What is the power of torch bulb rated at 2.5V and 500mA?
3. Why series arrangement not used for connecting domestic electrical appliances in a circuit?
4. Which has higher resistance – a 50W bulb or a 2.5W bulb and how many times?
5. What is the direction of flow of conventional current?
6. Calculate the amount of charge flowing in a wire if it draws a current of 2A in 10 minutes
7. What happens to resistance of a conductor if area of cross-section is doubled?
8. Which device helps to maintain a potential difference across a conductor?
9. Find the number of electron in 1C of charge.
10. Name the physical quantity whose unit is V/A.
11. Name the device that helps to maintain a potential a potential difference across a conductor.
TWO MARKS QUESTION
12. Draw a circuit diagram having the following components a. Bulb b. A two cell battery c. Ammeter d. A closed key
13. Why are heating elements made of alloys rather than metals?
14. What do we mean when we say that potential difference between two points is 1volt?
15. Why is it not advisable to handle electrical appliances with wet hands?
16. Two electric bulbs marked 100W 220V and 200W 200V have tungsten filament of same length. Which of the two bulbs will have thicker filament?
17. How does the resistance of a wire vary with its area of cross section?
18. Define electric potential? What is its SI unit.
19. State the factor on which at a given temperature the resistance of a cylindrical conductor depends. State the SI unit of resistivity.
20. A circuit has a line of 5 A. How many lamps of rating 40W, 200V can simultaneously run on this line safely.
THREE MARKS QUESTION
21. If three resistors of 6Ω, 9Ω and 21Ω are connected in series to a 12V battery, find
22. What are the advantages of connecting electrical devices in parallel with the battery rather than in series?
23. A geyser is rated 1500W, 250V. This geyser is connected to 250V mains. Calculate - The current drawn The energy consumed in 50hrs,The cost of energy consumed at Rs. 2.20 per kWh.
24. What is the function of an electric fuse? Name the material used for making fuse. In household circuit where is fuse connected?
25. Write one important advantage of using alternative current. How alternating current differ from direct current?
27. 2.4 x 10 20 electrons flow through a circuit in 10 hours. Calculate the magnitude of the current. [Charge on one electron = 1.6 x 10–19 C]. [1.066 x 10 – 3 ]
28. . 50 coulombs of charge is brought from infinity to a given point in an electric field when 62.5 j of work is done. What is the potential at that point? [1.25 V]
29. What is the electric potential at a point in an electric field when 24 j of work is done in moving a charge of 84 C from infinity?[0.285 V]
30. A charge of 75 C is brought from infinity to a given point in an electric field; when the amount of work done is 12.5 j. Calculate the electric potential at that point. [0.166 V]
FIVE MARKS QUESTION
31. Draw diagram showing three resistors R1, R2 and R3 in series. i)Two resistors of resistance 4Ω and 12Ω ii)In parallel iii)In series
32. Calculate the values of effective resistance in each case. (A) What is the function of fuse in an electric circuit? B) How is the SI unit of electric energy related to its commercial unit? (C) What would be the rating of the fuse for an electric kettle which is operated at 220V and consumes 500 W power?
33. a) State Ohms law. Derive the relation and give graphical representation for it. b) An electric oven rated at 500W is connected to a 220V line and used for 2 hours daily. Calculate the cost of electric energy per month at the rate of Rs.5 per KWh
MAGNETIC EFFECT OF CURRENT. ONE MARKS QUESTION
1. What is a solenoid?
2. What is the direction of the magnetic field lines inside a bar magnet?
3. What is the direction of the magnetic field lines outside a bar magnet?
4. State two uses of electromagnet.
5. An electron moving along X – axis in a magnetic field along Y – axis. In which direction will the electron deflected.
6. State Fleming’s left hand rule.
7. Name the sources of direct current.
8. What is the role of split ring in an electric motor?
9. What is an earth wire?
10. What is the surer test of magnetism?
11. What happens if we break a magnet into two pieces?
12. What is the effect of placing an iron core in a solenoid?
TWO MARKS QUESTION
13. What is an electromagnet?
14. What is the difference between a direct current and an alternating current? What is the frequency of AC in India?
15. State the rule to find the direction of magnetic field produced around a current-carrying conductor.
16. Give two points of difference between and electromagnet and permanent magnet.
17. Draw the lines of force indicating field direction of the magnetic field through and around Single loop of wire carrying electric current.
18. A solenoid carrying electric current. What is magnetic field? How is the direction of magnetic field at a point determined ? 19. How do the field lines of the regions of strong field different from those of weak field?
20. Give two advantages of electromagnets.
21. Give four features of domestic electric wiring.
22. Should a copper wire be used as a fuse wire? If not, why?
23. What is the importance of earth wire?
24. Explain the magnetic effects of current with the help of an activity along with a labeled diagram.
THREE MARKS QUESTION
25. What is the role of fuse, used in series with any electrical appliance? Why should a fuse with defined rating not be replaced by one with a larger rating?
26. Why does a magnetic compass needle deflect when a bar magnet or a current-carrying loop is brought near it. Draw a schematic diagram of domestic wiring system and write its main features.
27. Draw a labelled diagram to show how an electromagnet is made.
28. What is the purpose of the soft iron core in making an electromagnet?
29. Write two differences between AC and DC current and draw diagram also.
30. What is the solenoid ? Draw the field lines of the magnetic field produced on passing current through and around a current carrying solenoid.
FIVE MARKS QUESTION
31. Write principle of the electric generator. Explain construction and working of a generator. Draw labelled diagram of the electric generator.
32. Describe any five safety measure that should be taken while dealing with electric appliance connected in the domestic electric circuit.
SOURCE OF ENERGY
ONE MARKS QUESTION
1. Thermal power plants are set up near coal or oil fields. Give reason
2. Name the component of sunlight, exposure to which may cause skin cancer.
3. Flowing water possess which type of energy.
4. Name one place in India where wind energy power station is installed.
5. What is a solar panel?
6. What type of energy transformation takes place during winding of spring of a clock?
7. Name the process that produces a large amount of energy in the sun.
8. Why is biogas called a clean fuel?
9. Name the materials used for making solar cells.
TWO MARKS QUESTION
10. List two advantages and disadvantages each for using wind as a source of energy.
11. Write two differences between renewable and non – renewable sources of energy.
12. What is the principle of solar cooker? Name two types of solar cooker.
13. Name any two types of harmful nuclear radiations emitted during nuclear fission.
14. What is thermal power plant? Where it is preferably situated?
15. What is the use of black painted surface in solar heating devises.
16. Why are bio gas plants considered to be boon to the farmers? Give reason.
17. Hydroelectricity generated at a dam may be considered another form of solar energy. Why?
18. Why is charcoal considered to be a better fuel than wood?
19. Why a solar cooker cannot be used for frying or making chapattis?
20. Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?
21. Fire wood is our conventional fuel. List any four reasons for replacing it with the alternate sources of energy.
THREE MARKS QUESTION
22. What is a solarcell panel? List two advantages and disadvantages each of using Solar cells for producing electricity.
23. What is the principle of solar cooker? Give two limitations and two advantages of solar 30Name the fuel for hydropower plant. Mention two advantages and disadvantages of producing electricity at the hydropower plant.
24. Explain why: a. It is difficult to burn a piece of fresh wood from a tree. b. Pouring dry sand over the fire extinguishes it. c. It is difficult to use hydrogen as a source of energy.
25. What are the different types of energies obtained from the sea? Explain.
26. How is the slurry left over after the generation of biogas in biogas plant used?
27. In parabolic reflector type coolers, even temperature up to 1800C- 2000C can be attained. How?
28. Modern chulahs are more efficient than traditional chulahs. Why?
29. How is hydro energy converted into electrical energy?
30. Explain, why only a part of the solar energy that strikes the upper regions of atmosphere reaches the surface of the earth?
FIVE MARKS QUESTION
31. Describe the design and function of each part of a solar cooker with the help of a neat labelled diagram.

32. What is a principle of Biogas?Explain it working in brief.Draw a labelled diagram of biogas plant.