KSEEB - 10 SCIENCE - MODEL QUESTION PAPER - 2 - KEY ANSWER

 

    KSEEB - 10 SCIENCE     

      MODEL QUESTION PAPER - 2 (25-26)     

         KEY ANSWER       

        PART - A PHYSICS      

I. Multiple choice questions: 2 × 1 = 2

1. The S I unit of electric current is 

(A) ampere (A) 

(B) ohm (Ω)

(C) volt (V)

(D)  watt (W)

Ans:  (A) ampere (A)

2. Observe the figure given below. The magnetic field at the centre ‘C’ of circular coil is  

(A) zero    (B) I     (C) I1    (D) I2 

Ans: (A) zero

II. Answer the following questions : 2 x 1 = 2

3. Which mirror is used as rear view mirror? 

Ans:   Convex mirror.

4. List any two suggestions to avoid the overload in domestic electric circuit. 

Ans:

★ Live and neutral wires should not come into direct contact.

★ Too many appliances should not be connected to a single socket.

★ Should always use quality wires and good quality electrical appliances.   (Any two) 

III. Answer the following questions : 3 x 2 = 6 

5. Draw a simple electric circuit. Label ammeter and voltmeter. 

Ans:

6. An electric motor receives 10A electric current from 220V electric source. Find the power of motor.

Ans:

Given:

I = 10A

V = 220V

P = ?

P = V × I

P = 220 × 10 = 2200W

7. Draw a diagram of experiment conducted by Newton to show the recombination of white light. 

Ans:

IV. Answer the following questions : 3 x 3 = 9

8. a) State two laws of reflection of light. 

b) What is magnification of mirror? What does the negative sign indicate in the magnification value? 

OR 

Explain the activity which shows the refraction of light through a glass slab.    

a) 

i) The angle of incidence is equal to the angle of reflection. 

ii) The incident ray, the normal to the mirror at the point of incidence and the reflected ray, all lie in the same plane 

b)

★ The relative extent to which the image of an object is magnified with respect to the size of the object. / It is the ratio of height (size) of the image to the height (size) of the object. / Ratio of object distance and image distance

★ indicates that the image is real and inverted.

OR

Fix a sheet of white paper on a drawing board using drawing pins.

Place a rectangular glass slab over the sheet in the middle. Draw the outline of the slab with a pencil. Let us name the outline as ABCD.

Take four identical pins and fix two pins, say E and F, vertically such that the line joining the

pins is inclined to the edge AB.

Look for the images of the pins E and F through the opposite edge. Fix two other pins, say G and H, such that these pins and the images of E and F lie on a straight line.

Remove the pins and the slab. Join the positions of tip of the pins E and F and produce the line up to AB. Let EF meet AB at O. Similarly, join the positions of tip of the pins G and H and produce it up to the edge CD. Let HG meet CD at O′.

Join O and O′. Also produce EF up to P, as shown by a dotted line.

9. a) What is near-sightedness? 

b) What is power of accommodation of eye?  How does the eye accommodate to see distant objects? 

OR 

Stars appear to twinkle but the planets do not twinkle. Why? 

Ans:

a) The eye defect in which a person is able to see nearby objects clearly but not the distant objects.

b) 

★ The ability of the eye lens to adjust its focal length. 

While seeing the distant objects:

★ Ciliary muscles relax.

★ The focal length of the eye lens increases 

★ The eye lens becomes thin. 

OR

★Stars appear as point sources of light because they are very distant. 

★The light from a point source travels through the Earth's atmosphere, which has continuously changing refractive indices (atmospheric refraction). 

★This bending of light is inconsistent and leads to the apparent variation in the star's brightness, causing the twinkling effect.

 

★ Planets are much closer and appear as extended source. 

★ Due to their proximity, the average change in the amount of light reaching the eye from the different point sources of the planet nullifies the twinkling effect, so they do not twinkle.

10. a) What is solenoid? 

b) State Fleming’s left hand rule. 

c) What is the potential difference between live wire and neutral wire in domestic electric circuit in our country? 

Ans:

a) A coil of many turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid. 

b) Fleming's Left-Hand Rule states that if we stretch the thumb, forefinger, and middle finger of the left hand such that they are mutually perpendicular, the forefinger points in the direction of the magnetic field, the middle finger points in the direction of the current, and the thumb will point in the direction of the force.

c) 220V