# 1 MARK QUESTIONS for Class 10 PHYSICS

LIGHT – REFLECTION AND REFRACTION

Q1.  Is it possible that the laws of reflection change, if we use spherical mirror instead of a plane mirror? State your reasons.

Q2.  Out of convex mirror and concave mirror, whose focus is situated behind the mirror?

Q3.  Give the relationship of magnification with focal length of a spherical mirror.

Q4.  Between which two points of a concave mirror should an object be placed to obtain a magnification of -3?

Q5.  What is the velocity of light in a glass slab of refractive index 1.5?

Q6.   Is it possible that a convergent lens in one medium becomes divergent, when placed in another medium?

Q7.  If the magnification of a body of size 1 m is 2. What is the size of the image?

Q8.   When is the magnitude of the power of a lens equal to its focal length?

Q9. Define the term principal axis of a spherical mirror.

Q10. Define the principal focus of a concave mirror.

Q11. What is the magnification of the images formed by plane mirror and why?

Q12. We prefer a convex as a rear-view mirror in vehicles. Why?

Q13. Explain why a ray of light passing through the centre of curvature of a concave mirror, gets reflected along the same path.

Q14. What are the values of angle of incidence i and angle of reflection r for a normal incidence?

Q15. What is the unit of refractive index?

Q16. State a condition for no refraction of light entering from one medium to another.

Q17. Why is refractive index of atmosphere different at different altitudes?

Q18. How does the size of the image change as the object is brought closer from infinity towards the convex lens?

Q19.The refractive index of diamond is 2.42. What is the meaning of this statement?

Q20.  A ray of light incident on a concave mirror after passing through the centre of curvature is reflected back along the same path. What is the angle of incidence?

Q21.  What is the radius of curvature of a plane mirror?

Q22.   What is the power of sunglasses?

Q23.   Does refractive index change with colour of light?

Q24.  Redraw the ray diagram given below in your answer book and complete the path of ray. Direction In each of the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as

(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.

(b) If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.

(c) If Assertion is true, but Reason is false.

(d) If Assertion is false, but Reason is true.

(e) If Assertion and Reason both are false.

Q25. Assertion: Convex mirror is preferred for rearview mirror in vehicles.

Reason: The field view of a convex mirror is lesser than that of concave mirror.

Q26. Assertion: An object appears to be black.

Reason: All the light falling on the object is absorbed and only black light is reflected from it.

Q27. Assertion: Lateral displacement is the distance between incident ray and the emergent ray.

Reason: The wider the glass slab, the larger the lateral displacement.

Q28. Assertion: In the dispersion of white light by a prism, the red light bends the least.

Reason: The frequency of red light is the highest.

Q29. Assertion: The object distance is the distance of the object from the lens.

Reason: It is measured from the object to the optical centre of the Lens.

Q30.  The refractive index of a denser medium with respect to rarer medium is 5/4 then the refractive index of rarer medium with respect to denser medium will be

(a)5/4

(b) √5/2

(c) 2/√5

(d)4/5

Q31.  When an object is placed on the principal axis of a convex lens between first focus and optical centre, then position of image will be

(a) on same side of the lens as the object between first focus and optical centre

(b) on same side of the lens as the object and away from the first focus

(c) on opposite side of the lens as the object between second focus and optical centre

(d) on opposite side of the lens as the object and away from the second focus

Q32.  Which of the following mirrors are used to get powerful parallel beams of light in headlights?

(a) Plane mirrors

(b) Convex mirrors

(c) Concave mirrors

(d) Both (a) and (c)

Q33.  An object is placed at a distance of 10 cm in front of a concave mirror. It forms a real image three times larger than the object. The distance of image from the mirror is

(a) -30 cm

(b) 30 cm

(c) 10 cm

(d) -10 cm

HUMAN EYE AND THE COLOURFUL WORLD

Q1. Which part of the eye can be donated after death?

Q2.  Name the part of an eye which is equivalent to

(i)  diaphragm and

(ii)   photographic plate, in a camera.

Q3.  How is the sense of vision carried from the eye to the brain?

Q4. Which liquid fill in the space between eye lens and retina?

Q5. What is the nature of an image formed on the retina of the eye?

Q6. A man is wearing glasses of focal length + 1 m, what can be defect in the eye?

Q7. What is the twinkling of stars due to?

Q8.  On   what factor does the colour of the scattered light depends?

Q9.  Why are danger signal lights red in colour?

Q10.  What would have been the colour of the sky, if the Earth had no atmosphere?

Q11.  Bees are able to see ultraviolet light. Comment.

Q12. Define power of accommodation.

Q 13. What is the purpose of human eye?

Q14. State one function of iris in human eye.

Q15. What is the nature of image formed on the retina?

Q16. What is meant by dispersion of light?

Q17. What is tyndall effect?

Q18. Name the type of particles which acts as a prism in the formation of rainbow in the sky.

Q19. On which factor does the colour of the scattered white light depend?

Q20.  The sky appears dark to passengers flying at a very high altitude. Why?

Q21. What is the cause of dispersion of light passing through a prism?

Q22.  Which liquid is filled in the space between eye lens and retina?

Q23. Which part of eye acts as a cable which connects the eye with the brain?

Q24.  What is the nature of the image formed on the retina? What kind of lens is present in our eye?

Direction (Q Nos. 25 – 29) In each of the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as

(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.

(b)  If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.

(c)  If Assertion is true, but Reason is false.

(d) If Assertion is false, but Reason is true.

(e) If Assertion and Reason both are false.

Q25. Assertion: The least distance of distinct vision for a young adult with normal vision is 20 cm.

Reason: Far point for a human eye with normal vision is infinity.

Q26. Assertion: Tyndall Effect is an optical phenomenon of light used to explain atmospheric refraction.

Reason: The tiny particles of dust disperse sunlight in it falls through foliage in a forest.

Q27. Assertion: On a clear summer night twinkling of stars is observed.

Reason: The twinkling of stars is caused by dispersion of star light by the atmosphere.

Q28. Assertion: On mid-day, the colour of the sunlight becomes white.

Reason: No atmospheric refraction is caused due to overhead sun.

Q29. Assertion: Ciliary muscles adjust the size of the crystalline lens inside the human eye.

Q30. A person with a myopic eye cannot see object beyond -1.2 m distinctly. The power of the corrective lens used to restore proper vision is

(a)-0.830

(b) -0.920

(c) + 0.21 D

(d) +0.91 D

Q31.  At noon the sun appears white as:

(a) light is least scattered

(b) all the colours of the white light are scattered away

(c) blue colour is scattered the most

(d) red colour is scattered the most

Q32.  The danger signals installed at the top of tall buildings are red in colour. These can be easily seen from a distance because among all other colours, the red light

(a) is scattered the most by smoke or fog

(b) is scattered the least by smoke or fog

(c) is absorbed the most by smoke or fog

(d) moves fastest in air

Q33. A student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his textbook.  Which of the following statements is correct?

(a) The near point of his eyes has receded away

(b)  The near point of his eyes has come closer to him

(c)  The far point of his eyes has come closer to him

(d)  The far point of his eyes has receded away

Q34. What is dispersion? What happens when light is passed through a glass prism?

Q35. Why is it difficult to drive on a foggy day?

Q36. Explain, why the Sun overhead at noon, appears white?

Q37.  Calculate maximum power of accommodation of a person having normal vision.

Q38. Name the parts of our eyes that help us to focus near and distant objects in quick succession.

ELECTRICITY

Q1. Why closed path is required for the flow of current?

Q2. What causes the potential difference between the two terminals of a cell?

Q3.  A wire of resistivity is pulled to double its length. What will be its new resistivity?

Q4. In how much time will a bulb of 100 W consume an energy of 2 kWh?

Q5. How does the resistance of an ohmic conductor depend on the applied voltage?

Q6. What happens to the other bulbs in a series circuit, if one bulb blows off?

Q7. What is meant by potential difference between two points?

Q8. Name the device that helps to maintain a potential difference across a conductor.

Q9. State the relationship between 1 ampere and 1 coulomb.

Q10. A charge of 150 coulomb flows through a wire in one minute. Find the electric current flowing through it.

Q11. A given length of a wire is doubled and this process is repeated once again. By what factor does the resistance of the wire changes?

Q12. The resistance of a resistor is kept constant and the potential difference across its two ends is decreased to half of its former value.  State the change that will occur in the current through it.

Q13. Calculate the number of electrons constituting one coulomb of charge. (Charge on 1 electron = 1·6 × 10-19 C)

Q14. Write SI unit of resistivity.

Q15. Name the instrument used for measuring

(i) Potential difference

(ii) Current

Q16. Which is having more resistance – a 220 V, 100 W bulb or a 220 V, 60 W bulb.

Q17. Nichrome is used to make the element of electric heater. Why?

Q18.  Electric fuse is an important component of all domestic circuits. Why?

Q19.   You are given three bulbs of 40 W, 60 Wand 100 W. Which of them has lower resistance?

Direction (Q. No. 20- 24) In each of the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as

(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.

(b) If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.

(c) If Assertion is true, but Reason is false.

(d) If Assertion is false, but Reason is true.

(e) If Assertion and Reason both are false.

Q20. Assertion: The connecting wires are made of copper.

Reason: The electrical conductivity of copper is high.

Q21. Assertion: Resistors connected in series are more effective than those connected in parallel.

Reason: Resistance of resistors increase when connected in series.

Q22. Assertion: Domestic circuits are connected in Parallel.

Reason: Parallel circuits have same current in every part of the circuit.

Q23. Assertion: Two wires of same length and material have different areas of the cross-section.

Reason: The wire with the lower area of cross-section has the lower resistivity.

Q24. Assertion: Nichrome is used in making of heater rods.

Reason: Nichrome has high resistivity.

Q25. How much work is done in moving a charge of 2 C from a point of 118V to a point of 128V?

(a)20 J

(b)30 J

(c)40 J

(d)   10 J

Q26.  Which of the following terms does not represent electric power in a circuit?

(a) I2R

(b) IR2

(c) VI

(d) V2 /R

Q26.  What is the minimum resistance which can be made using five resistors each of 1/5Q?

(a) 1/5 Q

(b) 1/25 Q

(c) 1/10 Q

(d) 25 Q

Q27.  When a conducting wire is stretched to double of its initial length, then which property of conducting wire increases?

(a) Resistivity

(b) Resistance

(c) Volume

(d) Density

MAGNETIC EFFECTS OF ELECTRIC CURRENT

Q1. What is meant by a magnetic field?

Q2. How is the direction of magnetic field at a point determined?

Q3. Why are magnetic field lines closed curves?

Q4. Mention the shape of the magnetic field lines around a current-carrying straight conductor.

Q5. What type of core used to make an electromagnet?

Q6. Name the rule which gives the direction of induced current in a conductor.

Q7. State the rule which is used to find the direction of induced current.

Q8. How can it be shown that a magnetic field exists around a wire through which a direct current is passing?

Q9.  In a domestic electric circuit, mention the potential difference between live wire and neutral wire and frequency of AC?

Q10. What is the advantage of the earth wire connection in domestic electrical circuits?

Q11. Which is the most important safety method used for protecting home appliances from short-circuiting or overloading?

Q12. List two sources of magnetic fields.

Q13. Define the term ‘induced current’.

Q14. When a current-carrying conductor is kept in a magnetic field, state the position when maximum force acts on it.

Q15. State the conclusions that can be drawn from the observation that a current-carrying wire deflects a magnetic needle placed near it.

Q16. Mention the angle between a current-carrying conductor and magnetic field for which the force experienced by this current-carrying conductor placed in magnetic field is largest.

Q17. Suggest one way of discriminating a wire carrying current from a wire carrying no current.

Q18. Name any two sources of direct current.

Q19. Mention the advantage of A.C. over D.C. for long-distance transmission.

Q20. List anyone point of difference between A.C. and DC.

Q21. What is Short Circuit?

Q22.  Mention the name of three colours of the wires used in household wiring.

Q23. In which wire in an AC housing circuit, is the switch introduced to operate the light?

Q24. Why is an alternating current considered to be advantageous over direct current for long-range transmission of electric energy?

Direction (Q No. 25-29)In each of the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as

(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.

(b) If both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.

(c) If Assertion is true but Reason is false.

(d) If Assertion is false, but Reason is true.

(e) If Assertion and Reason both are false.

Q25. Assertion: A current-carrying conductor experiences a force in a magnetic field.

Reason: The force acting on a current-carrying conductor in a magnetic field is due to interaction between magnetic field produced by the current-carrying conductor and external magnetic field in which the conductor is placed.

Q26. Assertion: Electric Motor converts Electric Energy into mechanical Energy.

Reason: Electric motor is based on the principle of Flemings right-hand rule.

Q27. Assertion: Magnetic field lines do not intersect each other.

Reason: There cannot to two direction of the magnetic field at a point.

Q28. Assertion: The principle of Electromagnetic Induction was discovered by Michael Faraday.

Reason: The principle is used only in DC generators.

Q29. Assertion: Magnetic field can be created using a solenoid.

Reason: The strength of the magnetic field will depend on the number of turns of the solenoid.

Q30. The most important safety method used for protecting home appliances from short-circuiting or overloading is

(a) earthing

(b) use of fuse

(c) use of stabilizers

(d) use of electric meter

Q31. The essential difference between AC generator and DC generator is that

(a) AC generator has electromagnet while DC generator has permanent magnet

(b) DC generator generates higher voltage

(c) AC generator generates higher voltage

(d) AC generator has slip rings while DC generator has commutator

Q32.  The phenomenon of electromagnetic induction is

(a) the process of charging a body

(b) the process of generating magnetic field due to current passing through coil

(c) the process of producing induced current in a coil due to relative motion between a magnet and the coil

(d) the process of rotating a coil of an electric motor

Q33.  Which of the following property of a proton can change while it moves freely in a magnetic field?

(a) Mass

(b) Speed

(c) Velocity

(d) Momentum

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