Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

2551.

We cannot clearly see an object kept at a distance less than 25 cm from the eye.

Answer»

Solution :i. The MUSCLES attached to the eye lens (ciliary muscles) help in fine adjusbnents of the focal length of the lens.
II. The CAPACITY of these muscles to contract or relax to adjust the focal length (i.e., power of accommodation) has a limit.
iii. The minimum distance of an object from a normal eye for which the eye lens can decrease its focal length to the least possible value, is 25 cm. HENCE, we cannot clearly SEE an object kept at a distance less the 25 cm from the eye.
Discussion
2552.

Rectified spirit is an aqueoussolution which contains about ________ of ethanol .

Answer»

`95.5%`
`75.5%`
`55.5%`
`45.5%`

ANSWER :A
Discussion
2553.

Derive an expression for the pressure of an ideal gas in a container from Kinetic Theory and hence give Kinetic Interpretation of Temperature.

Answer»

Solution :Consider a cube of side .l. and an ideal GAS is filled in it. Let the co-ordinates, X, Y and Z will coincide with the sides of the cube. Let velocities of gas molecules along these directions are `V_(x), V_(y) and V_(z)`. Consider a gas molecule moving along X-axis with a velocity `V_(x)`. Its motion is perpendicular to Y-Zplane. Let the gas molecule SUFFERED elastic collision with Y-Z planeand bounced back. In this case the velocities `V_(y) and V_(z)` are not considered because collision is along X-direction only.

Change in MOMENTUM along X-direction is final momentum `(-mV_x)` - initial momentum `(mV_x) = -2mV_(x)` ...........(1)
Let area of one side of the cube is A. Then during the time `Delta t` only the molecules at a distance of `V_(x) Delta t` will collide with the walls. Let number of gas molecules in the volume `AVDelta t` are say.n.. In these molecules half of the molecules will move towards the wall and remaining will move away from the wall.
`:.` Amount of momentum transferred to the wall = Q
`= 2mV_(x) xx` number of molecules collided with wall
`:. Q = 2mV_(x) (1/2 nAV_(x)Delta t)`
Pressure on Y - Z plane =
`P_(x) = ("Rate of change in momentum")/("Area")`
`:. P = ("Force")/("Area") = (Q//Delta t)/(A)`
`= (2mV_(x).1/2 nAV_(x)Deltat)/(A Delta t) = nmV_(x)^(2)`
If behaviour of gas is isotropic that is equal in all directions then `V_(x) = V_(y) = V_(z)`
`:.` Root mean square velocity of gas
`=(V_(x)^(2)+V_(y)^(2)+V_(z)^(2))/(3) = 1/3 bar(V)^(2)`
Where `bar(V)^(2) = V_(x)^(2) + V_(y)^(2) + V_(z)^(2)`
`:.` Pressure of gas `P = 1/3 nmbar(V)^(2)`
From Pascal.s law pressure is same throught the container so pressure in any direaction (say x,y or z) is same.
Kinetic interpretation of temperature :
From gas equation
`PV = 1/3 nmbar(V)^(2) . V = 2/3 N (1/2) mbar(V)^(2))`
Where `N = nV` and `1/2 mbar(V)^(2)` = kinetic energy
for ideal gas internal energy is purely kinetic energy.
`:. E = n 1/2 mbar(V)^(2) :. PV = 3/2 E`
But `P = K_(B)NT`
`:. E = 3/2 PV = 3/2 K_(B)N.T`
But `E/N = 1/2 mV^(2) and E/N = 3/2 K_(B)T`
`:. E/N alpha T` is the average kinetic energy of gas molecule is proportional to absolute temperature of gas. But it does not DEPEND on volume of container.
Discussion
2554.

What is meant by Heating effect of electric current ?

Answer»

Solution :The passage of ELECTRIC CURRENT through a WIRE, results in the production of heat. This PHENOMENON is called heating effect of current. This heating effect of current is used in derices like electric heater, electric iron ETC.
Discussion
2555.

…….. is an spontaneous process.

Answer»

SOLUTION :NATURAL RADIOACTIVITY
Discussion
2556.

__________ were named as protons by Rutherford.

Answer»

SOLUTION :POSITIVE RAYS
Discussion
2557.

A person uses convex lens spectacles. What vision defect does he have? Draw a diagram (1) To show the defective eye (2) To show the correction with the lens

Answer»

Solution : A person USES convex LENS to cure his long SIGHT (hypermetropia)

Discussion
2558.

A magnetic field does not exert a force on

Answer»

a BAR magnet
a stationary ELECTRIC charge
an electromagnet
an electric charge moving perpendiculary to it

ANSWER :B
Discussion
2559.

Which device is used to produce electricity ? Describe with a neat diagram.

Answer»

Electric motor
Galvanometer
Electric current (DC)
voltmeter

SOLUTION :1.Electric generator (DC) is the device which is used to PRODUCE electricity.
2. This device converts mechanical energy into electrical energy.
3. This device WORKS on the principle of Faraday's Law of electromagnetic induction.
4. This can be harnessed for the use of mankind to produce largecurrent.
5. When the COIL of electric generator rotates inthe magnetic field, the magnetic field induces a current in this coil.
6. This INDUCED current then flows into the circuit connected to the coil with the help of the mechanical energy
Discussion
2560.

Suggest a few useful ways of utilising waste water .

Answer»

Solution :Waste water can be USED for the following ways :
(i)For recharging the ground water .
(II)Can be used for irrigation .
(iii) Treated municipal water can be used for WASHING cars or watering the gardens.
(iv)Certain POLLUTANTS in SEWAGE water can become fertiliser for various crops.
Discussion
2561.

Create a terrestrial food chain depicting four trophic levels.

Answer»

Solution :A terrestrial FOOD chain can be like :
`underset(("Producer"))underset("1st trophic level")("GRASS")rarr underset(("Herbivore"))underset("2nd trophic level")("Grasshopper")rarr underset(("CARNIVORE"))underset("3rd trophic level")("FROG")rarr underset(("Carnivore"))underset("4th trophic level")("Snake")`
Discussion
2562.

In figure, a ray of light PQ is incident normally on the hypotenuse of an isosceles right angled prism ABC. (a) complete the path of the ray PQ till it emerges from the prism. Mark in the diagram the angle wherever necessary. (b) what is the angle of deviation of the ray PQ ? (c) Name a device in which this action is used.

Answer»


ANSWER :(B) `180^(@),` (C) BINOCULAR
Discussion
2563.

The relation between electricity and magnetism was first established by ..........

Answer»

ANDRE Marie Ampere
Michael FARADAY
OERSTED
FLEMING

Answer :D
Discussion
2564.

What is electric circuit ?

Answer»

Solution :An electric circuit is a closed conducting (or) path, which has a network of electrical components through which ELECTRONS are ABLE to flow. This path is made USING electrical wires so as to CONNECT an electric appliance to a source of electric charges (battery).
Discussion
2565.

During ________ glucose is broken into pyruvic acid.

Answer»

Glycolysis
Kreb's cycle
Electron TRANSPORT CHAIN
 NONE of these

ANSWER :a
Discussion
2566.

Kanchi takes 5 mL of distilled water in four test tubes A, B, C and D. She dissolves sodium chloride in test tube A, potassium chloride in test tube B, calcium chloride in test tube C and magnesium chloride in test tube D. In which test tubes will soap give lather?

Answer»

Solution :Soap will give good lather in test tubes A and B because magnesium CHLORIDE and CALCIUM chloride make water HARD and REACT with soap to form scum.
Discussion
2567.

3 resistors R_1,R_2 and R_3 are connected in series to a battery. Draw the circuit diagram showing the arrangement. Derive an expression for the equivalent resistance of the combination. (b) Resistors are given as R_1=10 Omega, R_2=20 Omega and R_3=30 Omega. Calculate the effective resistance when they are connected in series . Also calculate the current flowing when the combination is connected to a 6V battery.

Answer»

Solution :(B) Here `R_1=10 Omega, R_2=20 Omega and R_3=30 Omega`
`therefore` Effective RESISTANCE in series `R=R_1+R_2+R_3=10+20+30=60 Omega`
As voltage of battery V=6V
`therefore` Current flowing in series COMBINATION of resistors
`I=V/R=(6V)/(60 Omega)=0.1A`
Discussion
2568.

Gather information about solar light solar water heating system and solar cooker.

Answer»

SOLUTION :Solar light : A solar light (solar lamp) converts the solar radiation into electrical energy using the photovoltaic effect. It consists of an LED lamp , solar PANEL solar controller and a BATTERY.
Solar waterheating SYSTEM : As solar water heating system uses sunlight for waterheating .It consists of a thermal collector which captures the heat from the sun and uses it to heat the water.
Solar cooker : Solar cooker is a device which can into heat energy. It works on the principle that black surface absorbs more heat than whiteor a reflecting surface.
Discussion
2569.

A cheetah, on seeing a prey, moves towards him at a very high speed. What causes the movement of his muscles ?How does the chemistry of cellular components of muscles change during this event?

Answer»

Solution :The site of prey acts as a stimulus in Cheetah and his nervous system send the impulse to its muscles to the limbs, resulting in its fast movement towards the prey.
When the stimulus is received the impulse travels along the nerve by electrical and chemical transmission. At the neuro-muscular junction, this CAUSE release of chemicals which are NEUROTRANSMITTERS.

When this chemical reaches the muscles, they MOVED by changing their shape.
Muscles cells have special proteins that CHANGE their shape and arrangement in the cell in RESPONSE to electrical impulse this leads to the excited action of the muscle cells which then spreads over the whole muscle fibre thereby causing it to shorten or contract.
Discussion
2570.

In Fig.1.35 a uniform bar of length l m is supported at its ends and loaded by a weight W kgf at its middle. In equilibrium find the reaction R_1 and R_2 at the ends.

Answer»

SOLUTION :`R_1=W/2 KGF and R_2=W/2 kgf`
Discussion
2571.

Explain the meanings of the words "electro magnetic" and induction in the term electromagnetic induction. List three factors on which the value of induced current produced in the circuit depends. Name and state the rule to determine the direction of induced current. State one practical application of this phenomenon in everyday life.

Answer»

Solution :Electromagnetic stands for the PROPERTY by which magnetism developed by a current of electricity. Induction stands for the action or process of bringing about or giving rise to something INDUCED current depends on:
The strength of magnelic field used.
(i) The rate of change of MAGNETIC FLUX associated with the coil.
(iii) The conductor in the form of coil of many turns of insulated wire.
Rule. Fleming right Hand Rule
Statement: Refer to Quick Review.
Application: Electric Generator .
Discussion
2572.

Name the technique by which doctors can produce pictures showing insides of the human body.

Answer»


ANSWER :N/a
Discussion
2573.

Name the safety measures commonly used in electric circuits and appliances.

Answer»

SOLUTION :EARTH WIRE and ELECTRIC FUSE wire .
Discussion
2574.

One word is incorrect in the statement . Change it to make the statement correct : Greek philosopher Linnaeus was the first to perform the animal classification.

Answer»

Solution :GREEK philosopher Aristotle was the FIRST to PERFORM the ANIMAL classification.
Discussion
2575.

One way of overcoming the energy crisis is to use more. . . . . . . . . .Bulbs.

Answer»

filament
glass
LCD
LED

Answer :D
Discussion
2576.

List five things you have done over the last one week to : (i) conserve our natural resources. (ii)Increase the pressure on our natural resources.

Answer»

Solution :(i) Five things that I have DONE over the LAST one week to conserve our natural resources are :
(i)Saved electricity by swithing off unnecessary lights.
(b)Repaired leaky taps for saving water.
(c )Used empty bottles of jams for storing purpose.
(d)Used empty plastic bottles of jams for storing purpose.
(e ) I have not purchased plastic TOYS.
(f ) I have not used petroleum products.
(ii)Five things which I have done over the last week to INCREASE thepressure on our natural resources :
(a) I did notswitch off my room .s light last night.
(b) Wasted food.
(c ) Wasted water during bathing.
(d)Frequently used heating devices.
(e )Visited my friends HOUSE in a car .
Discussion
2577.

We are using 'units's for measuring current. What does one unit equal ?

Answer»

SOLUTION :Unit = 1 kilo WATT HOUR
Discussion
2578.

Assertion (A) : A convex lens is called a convergent lens but a concave lens acts as a divergent lens. Reason (R) : A convergent lens is that which always forms a real image of a real object and a divergent lens is that which can never form a real image.

Answer»

Both (A) and (R) are true and (R) is correct explanation of the ASSERTION.
Both (A) and (R) are true but (R) is not the correct explanation of the assertion.
(A) is true but (R) is false.
(A) is false but (R) is true.

SOLUTION :Reason is false. A CONVERGENT lens is that which converges the incident light beam. However, a divergent lens diverges the incident beam of light.
Discussion
2579.

A man pulls a lawn roller through distance of 20 m with a force of 20 kg weight. If he applies the force at an angle of 60^(@) with the ground, calculate the power developed if he takes 1 min in doing so.

Answer»

SOLUTION :`P=W/t=(FS COS THETA)/t=32.66W`
Discussion
2580.

What is mean by rellection of sound? Explain. (a) Reflection at the boundary of a rarer medium (b) Reflection at the boundary of a denser medium (c) Reflection at sound in curved surfaces

Answer»

Solution :Reflection of Sound:
The bouncing of sound waves from the interface between two media is termed as the reflection of sound.
(i) Consider a wave travelling in a solid medium striking on the interface between the solid and the air. The compression exerts a force F on the surface of the rarer medium.
(ii) As a rarer medium has smaller resistance for any deformation, the surface of separation is pushed backwards.
(iii) As the particles of the rarer medium are free to move, a rarefaction is produced at the interface. Thus, a compression is reflected as a rarefaction and a RARE faction travels from right to left.

(i) A longitudinal wave travels in a medium in the form rarefactions. Suppose a of compressions and left to right reaches a rigid WALL.
(ii) The compression exerts a force F on the rigid wall. In turn, the wall exerts an equal and opposite reaction R=- F on the air molecules. This results in a compression near the rigid wall.
(iii) Thus, a compression travelling towards the rigid wall is reflected back as a compression. That is the DIRECTION of compression is reversed.

(i) When the sound waves are reflected from the curved surfaces, the intensity of the reflected waves is changed.
(ii) When reflected from a convex surface, the reflected waves are diverged out and the intensity is decreased.
(iii) When sound is reflected from a concave surface, the reflected waves are converged and focused at a point. So the intensity of reflected waves is concentrated at a point.
(iv) Parabolic surfaces are used when it is required to focus the sound at a particular point. Hence, many halls are DESIGNED with parabolic reflecting surfaces.
(v) In ELLIPTICAL surfaces, sound from one focus will always be reflected to the other focurs, no matter where it strikes the wall.
Discussion
2581.

What is the necessity of earthing an electric appliance ?

Answer»

Solution :In order to work an electric apparatus, we require TWO wires, one live wire and the other neutral. Due to wear and tear or due to excessive heating, sometimes live wire touches the BODY of the apparatus. Due to this we may get shock when we incidently touch the apparatus. To avoid the risk of electric shock, the metal body of the electric appliance is earthed i.e., a wire is connected to the cover of vessel on pne side and to the earth point THREE pin LUG. The oneend of the earth point is BURIED deep in the earth. Earth wire is usually given green or green yellow colour, the live wire is usually red or brown while black or light blue wire acts as a neutral wire.
Discussion
2582.

Planets do not twinkle.

Answer»

SOLUTION :SEE PAGE 291 of this BOOK.
Discussion
2583.

To transform the voltage and current levels : Transformer : : to convert DC solar power to AC solar power :_______________.

Answer»


Answer :INVERTER
Transformer is USED to transform the voltage and corrent levels of generated POWER. Similarly, inverter is used to CONVERT DC solar power to AC solar power.
Discussion
2584.

Choose the correct option. A rectangular coilof copper wire is rotated in a magnetic field. The direction of the induced current changes once in each

Answer»

TWO revolutions
one revolution
half revolution
one-fourth revolution

Answer :C
Discussion
2585.

The absolute refractive index of water is 1.36.What is the velocity of light in water ?

Answer»

Solution :Given : `v_(1)=3XX10^(8)`m//s,n=1.36
To FIND : velocity of light in water `(v_(2))`
n=`v_(1)/v_(2)`
1.36=`(3xx10^(8))/(v_(2))`
` v_(2)=(3xx10^(8))/(1.36)
`=2.21xx10^(8)` m//s
Velocity of light in water is `2.21xx10^(8)` m//s
Discussion
2586.

A ray of light suffers refraction through an equilateral prism. The deviation produced by the prism does not depend on the:

Answer»

ANGLE of incidence
colour of light
material of prism
size of prism

Answer :D
Discussion
2587.

What is the work of salaam Mumbai

Answer»

Solution :Salaam MUMBAI Foundationin PROGRAMS in various SCHOOLS in Mumbai to empower the slumdwelling children in the field of EDUCATION, sports arts and business, It also helps the children to improve their health andlifestyle through proper education.
Discussion
2588.

Under what conditions is the force experienced by a current carrying conductor placed in a uniform magnetic field maximum ?

Answer»

Solution :The force is MAXIMUM when the direction of current is at RIGHT ANGLES to the direction of magnetic FIELD.
Discussion
2589.

What is the electricpotentialof the neutralwire in a main supplycable

Answer»


SOLUTION :0 VOLT
Discussion
2590.

A mass 'M' is broken into two parts of masses m_1" and "m_2. How are m_1 " and "m_2 related so that force of gravitational attraction between the two parts is maximum.

Answer»

SOLUTION :Let `m_1= m" then "m_2= M-m`
Force between them when they are separated by distance 'r'
`F= (GM(M-m))/(r^2)= (G)/(r^2)(Mm-m^2)`
For F to the maximum, differentiate R w.r.t. m and EQUATE to zero
`(dF)/(dm)=(G)/(r^2)(M-2m)=0`
`M= 2m , m= (M)/(2)`
`M_1= m_2= (M)/(2)`.
Discussion
2591.

Assertion (A) : Esterification is a process in which a sweet smelling substance is produced.Reason (R) : When esters react with sodium hydroxide, an alcohol and sodium salt of carboxylic acid are obtained.

Answer»

Both (A) and (R) are true and (R) is correct explanation of the ASSERTION.
Both A and R are true but R is not the correct explanation of the Assertion.
(A) is true but (R) is FALSE.
(A) is false but (R) is true.

SOLUTION :Both A and R are true but R is not the correct explanation of the Assertion.
Discussion
2592.

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

Answer»

Solution :The RAY passing through the CENTRE of curvature is INCIDENT to the mirror ALONG its normal so `/_i=/_r=0`. Therefore, the ray retraces its path.
Discussion
2593.

What factors are considered in the predisaster management plan?

Answer»

Solution :i. The pre-disaster management plan includes the COMPLETE preparation and planning to face any type of disaster.
ii. The various factors considers this plan are as follows:
a. Identifying the areas prone to disaster.
b. Collecting information about intensity of disaster and probable sites DISASTERS by using intensity MAPS and hazard maps respectively.
c. Getting special traninig for disaster management.
d. INCREASING awareness about disaster management among the people through training PROGRAMMES, mass media etc.
Discussion
2594.

Two quantities A and B have different dimensions. Which mathematical operation given below is physically meaningful?

Answer»

`A//B`
`A+B`
`A-B`
`A=B`

ANSWER :A
Discussion
2595.

On what factors does the magnitude of force experienced by a current-carrying conductor placed normally in a magnetic field depend?

Answer»

SOLUTION :Force depends on (i) CURRENT flowing in the CONDUCTOR, (II) length of the conductor and (iii) strength of magnetic FIELD.
Discussion
2596.

Name the lens which can be used as a magnifying glass.

Answer»

Solution :A convex lens can be used as a magnigying GLASS so as to form magnified image of a tiny OBJECT PLACED NEAR it.
Discussion
2597.

Which of the following individual addiction can ruin the health of other people in the vicinity?

Answer»

ALCOHOLISM
DRUG ABUSE
SMOKING
Chewing gutkha

Discussion
2598.

(a) Expand the following abbreviations. (i)CHD (ii) BMI (iii) AIDS (iv) IDDM

Answer»

SOLUTION : (a) 1.CHD - Coronary Heart Disease
2.BMI - Body MASS INDEX
3.AIDS - Acquired Immuno Deficiency Syndrome 4.IDDM - Insulin Dependant Diabetes Mellitus
(b) The TWO types of STEM cells are

1.Embryonic stem cells
2.Adult or somatic stem cells
Discussion
2599.

Laughter club is a remady to away………….

Answer»


ANSWER :MENTAL STRESS
Discussion
2600.

Name one electric appliance working on the principle of heating effect of electric current.

Answer»

SOLUTION :ELECTRIC IRON
Discussion