important questions -paper 2

 

IMPORTANT QUESTIONS ------ PHYSICS (SCIENCE)

CLASS    X

 

1.      Distinguish between the terms “overloading and short circuiting” as used in domestic circuits.   (b) Why are the coils of electric toasters made of an alloy rather than a pure metal?

2.      What is meant by dispersion of white light? Describe the formation of rainbow in the sky with the help of a diagram.

3.       What is hypermetropia? Draw ray diagrams to show the image formation of an object by: (i) Hypermetropic eye.  (ii) Correction made with a suitable lens for hypermetropic eye.

4.      Give reason for the following: i)lour of the clear sky is blue.(ii) The sun can be seen about two minutes before actual    sunrise.(iii) We cannot see an object clearly if it is placed very close to the eyes.

5.      What is Presbyopia? Write two causes of this defect.

6.      .Draw a diagram to show the magnetic filed lines around a current carrying solenoid. What do you interpret from the pattern of the field lines?

7.      Difference between real and virtual images.

8.      Write any 4 uses of spherical mirrors.

9.      State the mirror formula.

10.  What is magnification . What is its SI unit.

11.  Draw a ray diagram of image formation when the object is placed in front of a convex lens at different position.

12.  What do you understand by spherical aberration and how it is corrected?

13.  Why do stars twinkle on a clear night?

14.  What is mirage? How does it occur?

15.  What is dispersion? How will you show that sun-light is composes of seven colours?

16.  What is the focal length of a plane mirror?

17.  Draw labelled diagram of human eye and describe its working.

18.  How do we see colours? What is colour blindness?

19.  What do you under stand by “least distance of distinct vision”.

20.  . What is persistence of vision? Write the process where it is used.

21.  Where will the image be formed when the object is placed between the focus and the pole (infinity, pole) of the convex mirror?

22.  With respect to air the refractive index of ice and that of rock salts are 1.31 and 1.54 respectively. Calculate the refractive index of rock salt with respect to ice.

 

 

 

 

23.  With respect to air the refractive index of water and that of benzene are 1.33 and 1.50 respectively. Calculate the refractive index of benzene with respect to water.

24.  A convex mirror used on a truck has 3m radius of curvature. If a bus is located at 5m from this mirror. Find the position, nature and size of the image.

25.  What is accommodation? What is the maximum variation in power of accommodation in human eye?

26.  An object of size 5cm is placed at a distance of 25cm from the pole of a concave mirror of radius of curvature 30cm. Calculate the distance and size of the image formed. What will be the nature of the image?

27.  An object of size 3cm is placed at a distance of 15cm from a convex lens of focal length 10cm. Calculate the distance and size of the image so formed. What will be the nature of image?

28.  Light enters from air to glass plate having refractive index 1.50. What is the speed of light if the speed of light in air is  m/s?

29.  What is dispersion? Which color of light deviates more on passing through a prism? When two prisms are placed together with one inverted and white light is passed, what will be the result? What are the conditions for the formation of rainbow? What are the values for the angle of incidence and angle of reflection for normal incidence?

30.  Which phenomenon does optic fiber work upon?

31.  An object is placed 20cm in front of mirrors M1 and M2 separately and image is found to be formed at a distance of 15cm in front of it in case of M1 and behind it in case of M2. Find the focal length and kind of mirror in each case.

 

 

 

important Questions/classX/cbse

IMPORTANT QUESTIONS ------ PHYSICS (SCIENCE)

                                           CLASS    X

 

 

1.      A charge of 400 C flows through a conductor for 1.3 minutes and 20 seconds. Finds the magnitude of the current flowing through the conductor.

2.      A charge of 5000 C flows through an electric circuit in 2 hour and 30 minutes. Calculate the magnitude of the current flowing through the circuit.

3.      A dry cell can supply a charge of 300 C. If the current is drawn from the cell is 60 mA, find the time in which the cell completely discharges. 

4.      A battery con supply a charge of 2.5 10⁵ C. If the current is drawn from the battery at a rate of 12.5 A, calculate the time in which the battery will be discharge.

5.      A dry cell can supply a charge of 800 c. If a continuous current of 8.0 mA is drawn, calculate the time in which cell will be discharged completely.

6.      A charge of 25 mA flows for 2 hour through a conductor. Calculate the number of electrons, which drift in the conductor. [Charge on one electron = 1.6 x 10 ^{– 19} C]. 

7.      Calculate the total number of electrons flowing through a circuit in 20 minutes and 40 seconds, if a current of 40 mA flows through the circuit. [Charge on one electron = 1.6 x 10 ^-19 C)

8.      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].

9.      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?  

10.  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?

11.  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.

12.  A charge of 2 C is moved in and electric field from infinity to two points A and B. If the work done in bringing the charge to point A is 12j and in bringing it to point B is 16 j. Calculate the potential difference between points A and B.

13.  Word of 25J and 30J is dome when 5 C charge is moved from infinity to a point A and then to a point B respectively. Calculate the potential difference between the points A and B.

14.  A charge of 25 C is moved from infinity to two points A and B in and electric field. The work done to do so up to A and B is 10 j and 12.5 j respectively. What is the potential difference between points A and B?

15.   The resistance of a wire of length 80 cm and of uniform area of cross-section 0.025 cm²,is found to be 1.50ohm. Calculate sp. Resistance of wire. 

16.  A wire of resistance 4.5ohm and length 150 cm, has area of cross-section of 0.04cm². Calculate sp. Resistance of wire.

17.  What should be the length of nichrome wire of resistance 4.5 ohm, if the length of similar wire is 60 cm and resistance 2.5 ohm?

18.  Resistance of a conductor of length 75 cm is 3.25 ohm. Calculate the length of a similar conductor, whose resistance is 16.25 ohm.

19.  A nichrome wires has a resistance of 5 ohm. Find the resistance of another nichrome wire, Whose length is four times and area of cross-section three times the first wire. 

20.  A resistance wire made from German silver has a resistance of 4.25 ohm. Calculate the resistance of another wire, made from same material. Such that its length increases by three times. 

21.  A nichrome wire of length l and area of cross-section A/4 has a resistance R. Another nichrome wire of length 3l and area of cross-section A/2 has resistance of R₁. Find the ratio of R₁ and R₂ .

22.  Write the nature of image formed by a plane mirror.

23.  What do you mean by conventional current flow?

24.  State Ohm's law. Give its mathematical form. Draw the graph showing the dependence of current on potential difference.

25.  When two resistors R₁ and R₂ connected in parallel to a source of energy, find the equivalent resistance.

26.  Why is the series arrangement not used for connecting domestic electric appliances in a circuit?

27.  Out of 60 W and 40 W lamps, which one has a higher electrical resistance when in use.

28.  Draw ray diagrams to represent the nature, position and relative size of the image formed by a convex lens for the object placed:  

         (a) at 2F1.   b) between F1 and the optical centre O of lens.