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.

7101.

What kind of mirror concave, covex or plain would be best suited for a solar cooker? Why.

Answer»

Solution :The solar cooker USES HEAT of the sunlight to cook the food , A concave mirror is used in order to reflect and focus sunlight at a PARTICULAR area. The temperature at the point increases thereby cooking and heating the food placed at that particular area
Discussion
7102.

(a) What do you understand by the term 'ultrasonic vibration'? (b) State three uses of ultrasonic vibrations. (c) Name three animals which can hear ultrasonic vibrations.

Answer»

Solution :Ultrasonic VIBRATION.
The vibrations whose frequencies are greater than 20000 Hz are called ultrasonic vibrations.
(b) (i) They are used in SONAR to measure the depth of sea (or ocean) and to locate under water OBJECTS.
(ii) It is used for scanning and imaging the position and GROWTH of a foetus and presence of stones in the gall bladder and kidney.
(iii) It is used for homogenising MILK in milk plants where fresh milk is agitated with ired quantity of fat and POWERED milk to obtain toned milk.
Mosquito, Dogs and Bats are the three animals that can hear ultrasonic vibrations.
Discussion
7103.

Nichrome is an alloy of lead and chromium.

Answer»

SOLUTION :NICHROME is an ALLOY of NICKEL and CHROMIUM.
Discussion
7104.

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R'then the ratio R/R' is -

Answer»

`(1)/(25)`
`(1)/(5)`
5
25

Answer :B
Discussion
7105.

A charge of 60 coulomb flows through a bulb in 5 minutes what is the current through the bulb ?

Answer»

2A
0.2 A
`12A`
0.12A

Solution :`I=(Q)/(t)=(60)/(5xx60)=1/5=0.2A`
Discussion
7106.

You observe that a gardener working in the park near your house collects the dry leaves from the garden and burns it. He also uses synthetic fertilisers for growth of plants. Answer the following questions based on the above information: (i) Which environmental values is the gardener disrespecting? (ii) How can the first activity be changed to make it environmental friendly? (iii) How can the second activity be changed to promote environmental health? (iv) Suggest one activity to inculcate such environmental values in students.

Answer»

Solution :(i) Environmental concern/Environmental health.
(ii) The leaves may be BURIED in the soil to produce manure.
(iii) ORGANIC manure may be used in place of synthetic fertilisers.
(iv) By creating proper awareness about the ill environmental IMPACT from EXISTING practices and benefits from changed practices. Group discussions/Debates/ Community service.
Discussion
7107.

Air pressure in car type increases during driving explain.

Answer»

Solution :During diving TEMPERATURE of the gas increases while its VOLUME remains constant. So according to CHARLE's law at constantV, `P prop T`. `therefore` PRESSURE of gas increases.
Discussion
7108.

Fill in the blank and explain the statement. Critical velocity does not depend on the . . . . . . . . . . . . . . of the satellite.

Answer»

SOLUTION :1.The satellite is GIVEN a specific velocity known as the critical velocity ( `v_c`) in a tangential direction to the orbit because of which the satellite starts revolving around the earth.
2. We KNOW by formula for Critical velocity `(v_c ) =sqrt((GM)/(R+h))`
Here, in this formula we can see that the critical velocity depends on mass of the earth (M), gravitation CONSTANT (G), radius of earth (R) and radius (h) of the orbit of satellite.
3. Hence, critical velocity does not depend on the mass of satellite.
Discussion
7109.

Body cavity between the body and internal organs is called …………

Answer»

Solution :Body CAVITY between the body and internal ORGANS is CALLED coelom.
Discussion
7110.

The unit of power of the lens is m.

Answer»

Solution :Correct statement - The unit of POWER of the lens is DIOPTRE or `m^(-1)`
Discussion
7111.

Velocity of sound in a gaseous medium is 330ms^(-1). If the pressure is increased by 4 timeswithout causing a change in the temperature, the velocity of sound in the gas is ...............

Answer»

`330ms^(-1)`
`660ms^(-1)`
`156ms^(-1)`
`990ms^(-1)`

Solution :Pressure has no effect on the VELOCITY of sound in the GAS. So velocity of sound remains UNCHANGED.
Discussion
7112.

A bulb is rated at 20 V -100 W. What is its resistance? Five such bulbs burn for 4 hours. What is the electrical energy consumed? Calculate the cost if the rate is Rs 4.60 per unit.

Answer»

<P>

Solution :(a) Calculation of Resistance: Here we know the voltage and power of the bulb. So, the resistance can be calculated by using the formula:
`P = (V^(2))/(R)`
Here, Power, `P = 100` watts
Voltage, `V = 200` volts
And, Resistance, `R = ?` (To be calculated)
Now, PUTTING these value in the above formula, we get:
`100 = ((200)^(2))/(R)`
`100 R = 40000`
And, `R = (40000)/(100)`
= 400 ohms
(b) Calculation of Electrical Energy Consumed. The electrical energy consumed in kilowatt-hours can be calculated by using the formula:
`E = P xx t`
Here, Power, `P = 100` watts
`= (100)/(1000)` kilowatt
`=0.1` kilowatt .......(1)
And, Time, `t = 4` hours ........(2)
So, Energy consumed by 1 bulb `= 0.1 xx 4`
`= 0.4` kilowatt-hours
And, Energy consumed by 5 bulbs `= 0.4 xx 5`
= 2 kilowatt-hours (or 2 KWH)
Thus, the total electrical energy consumed is ''2 kilowatt-hours'' or ''2 units''.
(C) Calculation of Cost of Electrical Energy. We have been given that:
Cost of 1 unit of electricity = Rs. 4.60
So, Cost of 2 units of electricity = Rs `4.60 xx 2`
= Rs 9.20
Discussion
7113.

What is the ratio of the moments of inertia of two rings radii r and nr about an axis perpendicular to their plane and passing through their centres?

Answer»

`1:n^(2)`
`1:n`
`1:2n`
`n^(2):1`

Solution :`I_(1)/I_(2) = (MR^(2))/(m(NR)^(2)) = 1:n^(2)`
Discussion
7114.

List three advantages of using solar cells.

Answer»

Solution :(i) Solar cells PROVIDE electricity in artificial satellites and SPACE probes.
(ii) Used for street lighting, for TRAFFIC signals, for operating water pumps etc.
(iii) Used to OPERATE electronic watches and CALCULATORS.
Discussion
7115.

During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio C_P//C_V for the gas is

Answer»

<P>`3/2`
`4/3`
2
`5/3`

Solution :The EQUATION of ADIABATIC CHANGE is
`P_V^(gamma)` = constant which gives
`P^(1-gamma)T^(gamma)` = constant
`P^(1-gamma)alpha1/T^gamma" or " P alphaT(gamma/(gamma-1))`
As`p alpha T^3:. gamma/(gamma-1)=3 " or " gamma=3/2`
Hence `C_P/C_V = =gamma=3/2`
Discussion
7116.

Followingare thetemperature- timegraphsobtainedby 4studentsin thisexperimentwhichoneis likelyto becorrect?

Answer»




ANSWER :D
Discussion
7117.

What will be the cost of using the s.ime for 1 month if one unit of electricity costs₹ 4 ?

Answer»

Solution :Energy consumed is 30 DAYS
`=0.6xx30 = 18 ` KWH
Cost of using 18 units = `₹ 4xx18 = ₹72`
Discussion
7118.

Trace the pathway followed by water molecules from the time it enters a plant root to the time it escapes into the atmosphere from a leaf.

Answer»

Solution : (i) During the replication of a DNA molecule, the new STRAND is synthesized in short segments which are called OKAZAKI fragments.
(ii) Root PRESSURE pushes water to stem to CAPILLARY actions Adhesion cohesion (results in rise up water (makes column of at the base of stem) (water molecules)toA Transpiration pull to Transpiration
Discussion
7119.

Choose the incorrect statement from the following regarding magnetic field lines:

Answer»

The DIRECTION of MAGNETIC field at a point is taken to be the direction in which the north pole of a magnetic compass needle POINTS.
Magnetic field lines are closed curves
If magnetic field lines are parallel and equidistant, they represent zero field strength
Relative strength of magnetic field is shown by the DEGREE of closeness of the field line.

Solution :Statement (C) is wrong. If magnetic field lines are parallel and equidistant they represent a uniform magnetic field.
Discussion
7120.

Obtainfollowing equation from first principles: (i) w=w_(0+a t (ii) q=w_(0)t+(1)/(2) a t^(2)

Answer»


ANSWER :CORRECT EXPRESSION
Discussion
7121.

What is the ideal mechanical advantage of a single fixed pulley ? Can it be used as a force multiplier?

Answer»


ANSWER :1
Discussion
7122.

What is the position of the centre of gravity of a: (a) rectangular lamina (b) cylinder?

Answer»

SOLUTION :(a) at the POINT of intersection of its DIAGONALS (b) At the mid point on the AXIS of CYLINDER.
Discussion
7123.

The thunder of cloud is heard 9.8 seconds later than the flash of lightning. If the speed of sound in air is 330ms^(-1) , what will be the height of the cloud?

Answer»

Solution : The height of the CLOUD (DISTANCE) - SPEED of sound `xx`time
`d=vxxt`
`=330xx9.8`
d=3224m
`:.` The height of the cloud is 3234 m
Discussion
7124.

For bodies which are not spherical or having an irregular shape, the direction of the force is along the line joiningtheir ______ .

Answer»

CENTRE of MASSES
Centres
Nearest EDGES
Both a and B

ANSWER :A
Discussion
7125.

A 60 Kg man goes around the earth in a satellite. In the satellite, his weight will be

Answer»

60 N
60 Kg
600 N
Zero

Solution :The person in a SATELLITE orbiting AROUND the earth is in weightlessness condition, hence his WEIGHT is zero.
Discussion
7126.

Cathode rays are discovered by ….

Answer»

SOLUTION :JJ THOMSON
Discussion
7127.

Explain Cartesian sign convention in case of refraction through lens.

Answer»

Solution :Cartesian sign conventions for lens:


i. Optical centre (0) of a lens is TAKEN as origin and principal axis oflens is taken as X-axis.
ii. All DISTANCES measured to the right of the origin are taken as positive, while distances measured to the left of the origin are taken as negative.
III. Distances measured perpendicular to and above the principal axis are taken as positive.
IV. Distances measured perpendicular to and below the principal axis are taken as negative.
Discussion
7128.

The object is always placed on_________ side of the lens.

Answer»

LEFT
right
top
bottom

Answer :A
Discussion
7129.

A bomb of mass 30 kg at rest explodes in to two pieces of masses 18 kg and 12 kg. The velocity of 18 kg mass is 6ms^(-1). The kinetic energy of the outer mass is

Answer»

324 J
486 J
256 J
5245 J

Solution :By conservation of momentum
`30xx0=18xx6+12+VtoV=-9ms^(-1)`
`K.E.=1/2 MV^(2)=486J`
Discussion
7130.

(translation, anticodon, tRNA, ,mRNA,' amino acids, triplet codon, transcription, DNA) The ……………………… formed in nucleus comes in cytoplasm. It brings in the coded message from ……………………….. The message contains the codes for amino acids. The code for each amino acid consists of three nucleotides. It is called as '........................'. Each mRNA is made up of thousands of triplet codons. As per the message on mRNA, ..................... are supplied by the ..................... . For this purpose, tRNA has '........................' having complementary sequence to the codon on mRNA. This is called '....................'.

Answer»

Solution :The mRNA formed in nucleus comes in cytoplasm. It brings in the coded message from DNA. The message contains the codes for AMINO ACIDS. The code for each amino acid CONSISTS of three NUCLEOTIDES. It is called as 'triplet codon'. Each mRNA is made up of thousands of triplet codons. As per the message on mRNA, amino acids are supplied by the tRNA. For this PURPOSE, tRNA has 'anticodon' having complementary sequence to the codon on mRNA. This is called 'translation'.
Discussion
7131.

How much time a satellite will take which is revolving in high earth orbit?

Answer»

Solution :A satellite revolving in an orbit 35780 km above the earth's SURFACE, will take around 24 hours to complete ONE REVOLUTION.
Discussion
7132.

Magnetic field at the centre of a current - carryingcicularring is inverslypropotionalto . ……. .

Answer»


ANSWER :1
Discussion
7133.

Which of the following energy sources cannot be used as an energy source on a cloudy day?

Answer»

GEOTHERMAL energy
tidal energy
Nuclear energy
solar energy

Answer :A
Discussion
7134.

The electronic configuration of metal A is 2,8,18,1. The metalA when exposed to air and moistureforms B a green layered compound. A with conc. H_2SO_4 forms C and D along with water . D is a gaseouscompound.Find A , B, C and D .

Answer»

Solution :(i)The electronic configuration of metal (A) is 2, 8, 18, 1…. A is copper (Z=29)
(ii) (A) Copper exposed to air and MOISTURE forms GREEN layered compound (B) that is copper CARBONATE.
`underset"(A)"(2Cu)+O_2 +CO_2 + H_2O to CuCO_3 .underset"(B)"(Cu(OH)_2)`
(iii) Copper (A) reacts with conc.`H_2SO_4`to give copper sulphate (C ) and Sulphur dioxide (D).
`underset"(A)"(Cu)+conc.2H_2SO_4 to underset"(C )"(CuSO_4) + underset"(D)"(SO_2) + 2H_2O`
Discussion
7135.

The defect of vision arises when the focal length of the eye is too long is

Answer»

Myopia
Cataract
Presbyopia
HYPERMETROPIA

Solution :Hypermetropia
Discussion
7136.

Malin village of Pune district, Maharashtra is known for which disaster?

Answer»

hailstorm
Landslide
Volcano
Radiation leakage

Answer :B
Discussion
7137.

While launching a satellite in itsorbit , the escape velocity is given to the satellite in tangential direction.

Answer»

SOLUTION :While LAUNCHING a SATELLITE in its orbit , the critical velocity is GIVEN to the satellite in tangential direction.
Discussion
7138.

Nametwoorganisms whichreproducesthroughbudding .

Answer»

SOLUTION :Budding takes PLACE in yeast and HYDRA.
Discussion
7139.

When 'n' number of resistors of equal resistance R connected in series, the equivalent resistance is R_(p)=(R )/(n)

Answer»

SOLUTION :CORRECT STATEMENT :`R_(s)=NR`
Discussion
7140.

The angular speed of a motor wheel is increased from 1200 rpm to 3120 rpm in 16 seconds, (i) What is its angular acceleration (assume the acceleration to be uniform) (ii) How many revolutions does the wheel make during this time ?

Answer»

SOLUTION :`ALPHA = 4PI rad s^(-1)`
N = 576
Discussion
7141.

…………… is a cold blooded animal.

Answer»

Bat
snake
RABBIT
ELEPHANT

ANSWER :b
Discussion
7142.

What is superficial expansion ?

Answer»

SOLUTION :If there is an INCREASE in the AREA of a solid object due to heating, then the expansion is CALLED superficial or Areal expansion.
Discussion
7143.

On whichmetallicpiece is the conductingwire wound to prepare an electromagnet ?

Answer»

COPPER
SOFTIRON
ALUMINIUM
NICHROME

SOLUTION :Softiron
Discussion
7144.

An object 5 cm in length is held 25 cm away a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and nature of the image formed.

Answer»

Solution :`{:("Concave lens",,),(f=+10 cm,h=+5cm,h.=?),(,u=-25 cm,v=?),(,,"Nature of image = Erect"):}`
Lens FORMULA `(L)/(v)-(l)/(u)=(l)/(f)`
`(l)/(v)-(l)/((-25))=(l)/(10), (l)/(v)-(l)/(10)-(l)/(25), (l)/(v)=(15)/(250)`
`v=+16.67 cm`
The image is formed at a distance of 16.67 cm on the right SIDE of the convex lens (+ sign signifies this)
Magnification `m=(v)/(u)=(h.)/(h)`
`m=((16.67))/((-25))=(h)/(5), -0.67=(h.)/(5), "" h.=-3.35 cm`
The image formed (h.) has a height of 3.35 cm which is less than object height (h). The image formed is diminished. h. has a-ve sign which INDICATES that the image formed is real and INVERTED.
Discussion
7145.

Form a group of students from your school to demonstrate the mock drill and demonstrate it in the school.

Answer»

SOLUTION :STUDENTS are EXPECTED to PERFORM this above ACTIVITY on their own.
Discussion
7146.

The process where wo lighter nucei fuse together to form a heavier nucleus is called

Answer»

NUCLEAR fission
nuclear fusion
Both a & b
None

Answer :A::C
Discussion
7147.

Fuses should be connected to the neutral wire

Answer»

Solution :FALSE. Reason : Fuses should be CONNECTED to the LIVE WIRE.
Discussion
7148.

Draw a schematic diagram of a circuit consisting of a battery of three cells of 2 V each, a 5Omega resistor, an 8Omega resistor, and a 12Omega resistor, and a plug key, all connected in series.

Answer»

Solution :A schematic diagram of a circuit consisting of a battery of THREE cells of 2 V each, a `5OMEGA` resistor, an `8OMEGA` resistor, and a `12 Omega` resistor, and a plug key, all connected in series is shown in FIGURE.
Discussion
7149.

By Newton's III - law of motion, the action force is not equal to the reaction force.

Answer»


Solution :CORRECT Statement : By Newton.s III - LAW of MOTION, the ACTION force is equal to the reaction force.
Discussion
7150.

A refrigerator transfers heat from the cold coling coils to the warmsurroundings. Is it against the second law of thermodynamics? Justify your answer?

Answer»

SOLUTION :No, EXTERNAL WORK is DONE.
Discussion