Class 10 Physics 2019 Supp Paper Solved

Class 10 Physics 2019 Supp

We have solved the FBISE Class 10 Physics 2019 Supp Past Paper in this post. For more Class 10 Solved Past Paper visit Here.

Class 10 Physics 2019 Supp Paper

Section A

Q1. MCQs

Not available

Q2.

(i) Give characteristics of simple harmonic motion ( SHM).

Ans. Following are the four characteristics of SHM:
1. A body executing SHM always vibrates about its mean position.
2. The acceleration of the body is always directed towards the mean position.
3.  The magnitude of the acceleration is directly proportional to the displacement of the body from the mean position. i.e. The acceleration is zero at the mean position and is maximum at the extreme position.
4.  The velocity of the body is maximum at the mean position and is zero at the extreme position.

(ii) What is SONAR? How is it helpful?

Ans. SONAR stands for Sound Navigation and Ranging. This is the technique used to locate underwater depths or is used for locating objects lying deep on the ocean floor etc. SONAR ranging is also used to see the shape and the size of the object.

(iii) Calculate the intensity level of the rustling of leaves.

Sol.  Intensity of rustling of leaves = I =   10^-11 Wm^-2
Intensity of faintest audible sound = I_o = 10^-12 Wm^-2           
Intensity level = L – L_o =?

Using formula
L – L_o = 10 log (I / I_o )
L – L_o = 10 log (10^-11 / 10^-12)
L – L_o = 10 log 10
L – L_o = 10 (1)
L – L_o = 10 dB

(iv) Does increasing the frequency of a wave also increase its wavelength? If not, how are these quantities related?

Ans. No, increasing the frequency does not increase the wavelength. When we increase the frequency, the wavelength is decreased. The relationship between frequency, wavelength, and velocity of a wave is called the wave equation. The wave equation is given below:
v = f λ

(v) An object and its image in a concave mirror are of the same height, yet inverted when the object is 20cm
from the mirror. What is the focal length of the mirror?

(vi) Discuss one application of static electricity.

Ans. An electrostatic air cleaner is used in homes to relieve the discomfort of allergy sufferers. Air mixed with dust and pollen
enters the device across a positively charged mesh. The airborne particles become positively charged when they make contact with the mesh. Then they pass through a second, negatively charged mesh. The electrostatic force of attraction between the positively charged particles in the air and the negatively charged mesh causes the particles to precipitate out on the surface of the mesh. Through this process, we can remove a very high percentage of contaminants from the air stream.

(vii) By applying a potential difference of 10V across a conductor, a current of 1.5 A passes through it. How much energy would be obtained from the current in 2 mins?

(viii) For a metal wire as a conductor, show that R = ρ L / A.

Ans. Electrical resistance also depends on temperature. At a certain temperature and for a particular substance:
1. The resistance R of the wire is directly proportional to the length of the wire i.e.,
R ∝ L ……(i)
It means if we double the length of the wire, its resistance will also be doubled, and if its length is halved, its resistance
would become one half.
2. The resistance R of the wire is inversely proportional to the area of cross-section A of the wire i.e.,
R ∝ 1 / A …… (ii)
It means that a thick wire would have smaller resistance than a thin wire.
After combining the two equations, we get
R ∝ L / A
R = ρ L / A

(ix) What is an ideal transformer? Give its equation.

Ans. The transformer in which, the electric power delivered to the secondary circuit is equal to the power supplied to the
primary circuit is called an ideal transformer. An ideal transformer dissipates no power itself. The equation of the ideal transformer can be written as:
P_s = P_p
V_p I_p = V_s I_s

(x) What are the main differences between a motor and a generator?

Ans. The main difference between a motor and a generator is that a motor converts electrical energy into mechanical energy while a generator converts mechanical energy into electrical energy.

(xi) What are the factors which affect the magnitude of the emf induced in a circuit by a changing magnetic field?

Ans. Factors Affecting Induced e.m.f
The magnitude of induced e.m.f in a circuit depends on the following factors:
1 . Speed of relative motion of the coil and the magnet
2. Number of turns of the coil

(xii) Give some uses of the oscilloscope.

Ans. The CRO is used in many fields of science; displaying waveforms, measuring voltages, range-finding (as in radar), echo-sounding (to find the depth of seabeds). The CRO is also used to display heartbeats.

(xiii) Briefly describe the computer hard disk.

Ans. Hard Disk: Most users rely on hard disks as their primary storage devices. A hard disk is a rigid, magnetically sensitive disk that spins rapidly and continuously inside the computer chassis or in a separate box connected to the computer housing. This type of hard disk is never removed by the user. A typical hard disk consists of several platters, each accessed via a read/write head on a moveable arm.

(xiv) Differentiate between the terms ‘word processing’ and ‘data managing’.

Ans. Word processing is such a use of the computer through which we can write a letter, article, book, or prepare a report. Word processing is a computer program. Using this program we can develop any document, and see it on the screen after typing.
To collect all information regarding a subject for any purpose and to store them in the computer in more than one inter
linked files which may help when needed is called ‘data managing‘.

(xv) The 14 – C : 12 – C ratio in the fossil bone is found to be 1/4 th that of the ratio in the bone of living animal. The half-life of 14 – C is 5730 years. What is the approximate age of the fossil?

Sol.  Half-life of Carbon-14 = T_½ = 5730 Years
Fraction of original sample left = N / N_o = 1 / 4
Time of decay (approximate age of the fossil) = T =?
 Using         1 / 2^t = N / N_o        
1 / 2^t = 1 / 4
1 / 2^t = 1 / 2²
t = 2
Now using
Time of decay = No of half-lives × Half life                                                           
T = t × T_½
T = 2 × 5730 Years
T = 11460  Years
Hence the approximate age of the fossil = T = 11460  Years

Class 10 Physics 2019 Supp Paper
Section C

Attempt any Two Questions

Q3. a. What is meant by the terms near-sightedness and far-sightedness’’? How can these defects be removed? Elaborate with diagram. (6)

Ans. Nearsightedness (myopia)
Some people cannot see distant objects clearly without the aid of spectacles. This defect of vision is known as short sight or nearsightedness and it may be due to the eyeball being too long. Light rays from a distant object are focused in front of the retina and a blurred image is produced.

Correction: The nearsighted eye can be corrected with glass or contact lenses that use diverging lenses. Light rays from distant objects are now diverged by this lens before entering the eye.

Farsightedness (hypermetropia)
The disability of the eye to form distinct images of nearby objects on its retina is known as farsightedness.

Correction: This defect can be corrected with the aid of a suitable converging lens. The lens refracts the light rays and they converge to form an image on the retina.

Q3. b. Find the time periods of a simple pendulum of 1m length, placed on earth and on the moon. The value of g on the surface of the moon is 1/6^th of its value on Earth, where g_e = 10 ms^-2. (4)

Q4. a. How are capacitors combined in series? Describe with diagram. Also derive the formula for the equivalent capacitance for a series combination of a number of capacitors. (6)

Ans. Capacitors in Series: In this combination, the capacitors are connected side by side i.e., the right plate of one capacitor is connected to the left plate of the next capacitor.

Q4. b. If the length of copper wire is 1 m and its diameter is 2 mm, then find the resistance of this copper wire. (4)

Example 14.3 Page 100