13232 + Interview Questions in Physics Page 98 InterviewSolution

4851.	What type of frequencies do bats use for echolocation?
Answer» What type of frequencies do bats use for echolocation?

Discussion

4852.	27.When an object is vertically thrown downward from a certain height H.why do we take u =-u, a = -g, s = - H, v = -v? Even acceleration is negative. Why?
Answer» 27.When an object is vertically thrown downward from a certain height H.why do we take u =-u, a = -g, s = - H, v = -v? Even acceleration is negative. Why?

Discussion

4853.	What do you mean by green house effect?
Answer» What do you mean by green house effect?

Discussion

4854.	UV rays act on chlorofluorocarbons (CFCs) and release __________ which degrades the ozone layer in the stratosphere.
Answer» UV rays act on chlorofluorocarbons (CFCs) and release __________ which degrades the ozone layer in the stratosphere.

Discussion

4855.	why a ray emerges parallel to the incident ray
Answer» why a ray emerges parallel to the incident ray

Discussion

4856.	32. Two bodies are in equilibrium when suspended in water from the arms of a balance. The mass of one body is 36 g and its density is 9 g/cc. If the mass of the other is 48 g, its density in g/cc is 1. 4/3 2. 3/2 3. 3 4. 5 Click here to view details:
Answer» 32. Two bodies are in equilibrium when suspended in water from the arms of a balance. The mass of one body is 36 g and its density is 9 g/cc. If the mass of the other is 48 g, its density in g/cc is 1. 4/3 2. 3/2 3. 3 4. 5 Click here to view details:

Discussion

4857.	calculate the energy spent in spraying a drop of mercury 1 cm radius into 10^{6 _{}}droplets all of same size. surface tension=35×10^{-3}N/m^2.
Answer» calculate the energy spent in spraying a drop of mercury 1 cm radius into 10^{6 _{}}droplets all of same size. surface tension=35×10^{-3}N/m^2.

Discussion

4858.	An object moves with an acceleration of 3ms2 when a force of 30 N is applied. The mass of the body is ___ kg.
Answer» An object moves with an acceleration of $3 \frac{m}{s^{2}}$ when a force of 30 N is applied. The mass of the body is ___ kg.

Discussion

4859.	A body is moving uniformly in a straight line with a velocity of 5 m/s. Find graphically the distance covered by it in 5 seconds.
Answer» A body is moving uniformly in a straight line with a velocity of 5 m/s. Find graphically the distance covered by it in 5 seconds.

Discussion

4860.	What is mechanical strength
Answer» What is mechanical strength

Discussion

4861.	Question 8Water stored in a dam possesses(a) no energy(b) electrical energy(c) kinetic energy(d) potential energy
Answer» Question 8 Water stored in a dam possesses (a) no energy (b) electrical energy (c) kinetic energy (d) potential energy

Discussion

4862.	what is the difference between optimum speed and maximum speed during banking of roads? Also explain that at optimum speed the friction force is not required to produce centripetal force
Answer» what is the difference between optimum speed and maximum speed during banking of roads? Also explain that at optimum speed the friction force is not required to produce centripetal force

Discussion

4863.	The number of significant figures in the distance of one light year , 9.4605 × 10 15 m is
Answer» The number of significant figures in the distance of one light year , 9.4605 × 10 ¹⁵ m is

Discussion

4864.	83. A solid sphere of radius R is placed on a smoothhorizontal surface. A horizontal force F is applied atheight h from the lowest point. For the maximumacceleration of centre of mass, which is correct?(1) h R(2) h=2R(3) h=0(4) Centre of mass has same acceleration ineach case
Answer» 83. A solid sphere of radius R is placed on a smoothhorizontal surface. A horizontal force F is applied atheight h from the lowest point. For the maximumacceleration of centre of mass, which is correct?(1) h R(2) h=2R(3) h=0(4) Centre of mass has same acceleration ineach case

Discussion

4865.	5 A piece of solid is embedded inside an ice block when floats in water.when ice melts completely,the level of water 1)remains same,if dsdw and 2) falls ,if ds>dw. HOW?
Answer» 5 A piece of solid is embedded inside an ice block when floats in water.when ice melts completely,the level of water 1)remains same,if dsdw and 2) falls ,if ds>dw. HOW?

Discussion

4866.	Difference between echo and reverberation?
Answer» Difference between echo and reverberation?

Discussion

4867.	What are the 2 factors affecting buoyant force
Answer» What are the 2 factors affecting buoyant force

Discussion

4868.	Find the energy KWh consumed in 10 hours by four devices of power 500?
Answer» Find the energy KWh consumed in 10 hours by four devices of power 500?

Discussion

4869.	Draw a graph for acceleration against time for a uniformly accelerated motion.How can it be used to find the change in speed in a certain interval of time?
Answer» Draw a graph for acceleration against time for a uniformly accelerated motion.How can it be used to find the change in speed in a certain interval of time?

Discussion

4870.	If v=3 + ax, where a is a cons†an t then draw the acceleration Vs time graph andalso write the nature of graph.
Answer» If v=3 + ax, where a is a cons†an t then draw the acceleration Vs time graph andalso write the nature of graph.

Discussion

4871.	Which of the following forces helps us walk on ground?
Answer» Which of the following forces helps us walk on ground?

Discussion

4872.	1. A uniform flexible chain of mass m and length l hangs in equilibrium over a smooth horizontal pin of negligible diameter. One end of the chain is given a small vertical displacement so that the chain slips over. The speed of chain when it leaves pin is
Answer» 1. A uniform flexible chain of mass m and length l hangs in equilibrium over a smooth horizontal pin of negligible diameter. One end of the chain is given a small vertical displacement so that the chain slips over. The speed of chain when it leaves pin is

Discussion

4873.	What is the distance travelled by a body and its displacement when it completes one revolution around a circular track with radius r?
Answer» What is the distance travelled by a body and its displacement when it completes one revolution around a circular track with radius $r$ ?

Discussion

4874.	An object thrown vertically upwards, rises to a maximum height of 10 m. What is the velocity with which it is thrown upwards? (Take g=9.8 m s−2)14
Answer» An object thrown vertically upwards, rises to a maximum height of $10 m$ . What is the velocity with which it is thrown upwards? (Take $g = 9.8 m s^{- 2}$ ) 14

Discussion

4875.	If a body travels very large distance compared to its size, then the body is considered to be a
Answer» If a body travels very large distance compared to its size, then the body is considered to be a

Discussion

4876.	why a cell always gives a smaller amount of current ?
Answer» why a cell always gives a smaller amount of current ?

Discussion

4877.	What type of waves are generated by SONAR device fixed to a fishing ship ? (a) water waves (b) radio waves (c) sound waves (d) infrared waves
Answer» What type of waves are generated by SONAR device fixed to a fishing ship ? (a) water waves (b) radio waves (c) sound waves (d) infrared waves

4877.

What type of waves are generated by SONAR device fixed to a fishing ship ? (a) water waves (b) radio waves (c) sound waves (d) infrared waves

Answer»

What type of waves are generated by SONAR device fixed to a fishing ship ?

(a) water waves

(b) radio waves

(c) sound waves

(d) infrared waves

Discussion

4878.	18.If acceleration a=4-4t/2,then find average acceleration for t=1 to 2 sec
Answer» 18.If acceleration a=4-4t/2,then find average acceleration for t=1 to 2 sec

Discussion

4879.	The temperature at which a black body of unit area loses its energy at the rate of 1 joule/second is
Answer» The temperature at which a black body of unit area loses its energy at the rate of 1 joule/second is

Discussion

4880.	A truck of mass 5000 kg is moving with a velocity of 20 ms−1. To avoid an accident, the driver applies brakes to stop the truck in 5 seconds. Calculate the force applied by the brakes in order to stop the truck in the given time using work-energy theorem.
Answer» A truck of mass 5000 kg is moving with a velocity of 20 ms $^{- 1}$ . To avoid an accident, the driver applies brakes to stop the truck in 5 seconds. Calculate the force applied by the brakes in order to stop the truck in the given time using work-energy theorem.

Discussion

4881.	If 250 J of work is done in sliding a 5 kg block up an inclined plane of height 4m. Work done against friction is
Answer» If 250 J of work is done in sliding a 5 kg block up an inclined plane of height 4m. Work done against friction is

Discussion

4882.

Consider the following table for an LTI system having an impulse response h(t). Input Output x(t) y(t) ddtx(t) −3y(t)+e−2tu(t)where, x(t)=2e−3tu(t−1)Then the impulse response h(t) of the system is

Answer»

Consider the following table for an LTI system having an impulse response h(t).

Input	Output
x(t)	y(t)
$\frac{d}{d t} x (t)$	$- 3 y (t) + e^{- 2 t} u (t)$

where,

x (t) = 2 e^{- 3 t} u (t - 1)

Then the impulse response h(t) of the system is

Discussion

4883.	What mass of phosphorous is needed to dope 1.0 g of silicon so that the number density of conduction electrons in the silicon increased by a multiply factor of 106 from the 1016 m−3 in pure silicon.(Take the concentration of silicon atoms nSi=5×1028 m−3Molar mass of silicon MSi=28.1 gMolar mass of phosphorous MP=30.97 gAvogadro number NA=6.023×1023)
Answer» What mass of phosphorous is needed to dope $1.0 g$ of silicon so that the number density of conduction electrons in the silicon increased by a multiply factor of $10^{6}$ from the $10^{16} m^{- 3}$ in pure silicon. (Take the concentration of silicon atoms $n_{Si} = 5 \times 10^{28} m^{- 3} Molar mass of silicon M_{Si} = 28.1 g Molar mass of phosphorous M_{P} = 30.97 g Avogadro number N_{A} = 6.023 \times 10^{23})$

Discussion

4884.	The value of resis†an ce determined by colour bands of a carbon resistor is 0.51 + 10% . Write the colours of bands in corect order.
Answer» The value of resis†an ce determined by colour bands of a carbon resistor is 0.51 + 10% . Write the colours of bands in corect order.

Discussion

4885.	A ball of mass m is thrown vertically up with an initial velocity so as to reach a height h.The correct statement is : (a) Potential energy of the ball at the ground is mgh. (b) Kinetic energy of the ball at the ground is zero. (c) Kinetic energy of the ball at the highest point is mgh. (c) Potential energy of the ball at the highest point is mgh.
Answer» A ball of mass m is thrown vertically up with an initial velocity so as to reach a height h.The correct statement is : (a) Potential energy of the ball at the ground is mgh. (b) Kinetic energy of the ball at the ground is zero. (c) Kinetic energy of the ball at the highest point is mgh. (c) Potential energy of the ball at the highest point is mgh.

4885.

A ball of mass m is thrown vertically up with an initial velocity so as to reach a height h.The correct statement is : (a) Potential energy of the ball at the ground is mgh. (b) Kinetic energy of the ball at the ground is zero. (c) Kinetic energy of the ball at the highest point is mgh. (c) Potential energy of the ball at the highest point is mgh.

Answer»

A ball of mass m is thrown vertically up with an initial velocity so as to reach a height h.The correct statement is :

(a) Potential energy of the ball at the ground is mgh.

(b) Kinetic energy of the ball at the ground is zero.

(c) Kinetic energy of the ball at the highest point is mgh.

(c) Potential energy of the ball at the highest point is mgh.

Discussion

4886.	The following' precautions' were listed by a student in the experiment on study of 'Dependence of current on potential difference'.(A) Use copper wires as thin as possible for making connections.(B) All the connections should be kept tight.(C) The positive and negative terminals of the voltmeter and the ammeter should be correctly connected.(D) The 'zero error' in the ammeter and the voltmeter should be noted and taken into consideration while recording the measurements.(E) The 'key' in the circuit, once plugged in, should not be taken out till all the observations have been completed.The 'precautions' that need to be corrected and revised are:(1) (A), (C) and (E)(2) (C) and (E)(3) (B) and (E)(4) (A) and (E)
Answer» The following' precautions' were listed by a student in the experiment on study of 'Dependence of current on potential difference'. (A) Use copper wires as thin as possible for making connections. (B) All the connections should be kept tight. (C) The positive and negative terminals of the voltmeter and the ammeter should be correctly connected. (D) The 'zero error' in the ammeter and the voltmeter should be noted and taken into consideration while recording the measurements. (E) The 'key' in the circuit, once plugged in, should not be taken out till all the observations have been completed. The 'precautions' that need to be corrected and revised are: (1) (A), (C) and (E) (2) (C) and (E) (3) (B) and (E) (4) (A) and (E)

Discussion

4887.	a wire of given material having length I and area of cross section A has a resis†an ce of 4ohms .what would be the resis†an ce of another wire of the same material having length 1/2 and area of crossection 2A
Answer» a wire of given material having length I and area of cross section A has a resis†an ce of 4ohms .what would be the resis†an ce of another wire of the same material having length 1/2 and area of crossection 2A

Discussion

4888.	A bus travelled the first one-third distance at the speed of 10 km/h, the next one-third at 20 km/h and the last one-third at 60 km/h. The average speed of the bus is :
Answer» A bus travelled the first one-third distance at the speed of $10 km/h$ , the next one-third at $20 km/h$ and the last one-third at $60 km/h$ . The average speed of the bus is :

Discussion

4889.	The people in a bus are pushed backwards when the bus starts suddenly because of:
Answer» The people in a bus are pushed backwards when the bus starts suddenly because of:

Discussion

4890.	A thin rod of length f3 is placed along the optic axis of a concave mirror of focal length f such that its image which is real and elongated just touches the rod. The magnification is:
Answer» A thin rod of length $\frac{f}{3}$ is placed along the optic axis of a concave mirror of focal length $f$ such that its image which is real and elongated just touches the rod. The magnification is:

Discussion

4891.	104.A car is approaching towards a stationary observer with the speed 10 m/s while blowing whistle of frequency f= 440 Hz. The frequency of whistle heared by observer is ( given speed of sound = 340)
Answer» 104.A car is approaching towards a stationary observer with the speed 10 m/s while blowing whistle of frequency f= 440 Hz. The frequency of whistle heared by observer is ( given speed of sound = 340)

Discussion

4892.	Which type of colour did Thomson observed when he found electrons while cathode rays experiment?
Answer» Which type of colour did Thomson observed when he found electrons while cathode rays experiment?

Discussion

4893.	Question 129(ii) The table shows the mass of the planets, the Sun and the Moon in our solar system. Order the planets and the Moon by mass, from least to greatest.
Answer» Question 129(ii) The table shows the mass of the planets, the Sun and the Moon in our solar system. Order the planets and the Moon by mass, from least to greatest.

4893.

Question 129(ii) The table shows the mass of the planets, the Sun and the Moon in our solar system. Order the planets and the Moon by mass, from least to greatest.

Answer»

Question 129(ii)

The table shows the mass of the planets, the Sun and the Moon in our solar system.

Order the planets and the Moon by mass, from least to greatest.

Discussion

4894.	In myopic eye , when we stretch our eye muscles , why we can see far objects more clearer without spectacles?
Answer» In myopic eye , when we stretch our eye muscles , why we can see far objects more clearer without spectacles?

Discussion

4895.	A steel wheel of 600 mm diameter rolls on a horizontal steel rail. It carries a load of 500 N. The coefficient of rolling resistance is 0.3 . The force in N, necessary to roll the wheel along the rail is
Answer» A steel wheel of 600 mm diameter rolls on a horizontal steel rail. It carries a load of 500 N. The coefficient of rolling resistance is 0.3 . The force in N, necessary to roll the wheel along the rail is

Discussion

4896.	In a fight, a man fires 50g bullets from a machine gun, each at a speed of 1.0 km/s. If he fires 20 bullets in 4 seconds, what average force does he exert against the machine gun during this period?
Answer» In a fight, a man fires 50g bullets from a machine gun, each at a speed of 1.0 km/s. If he fires 20 bullets in 4 seconds, what average force does he exert against the machine gun during this period?

Discussion

4897.	what is vector laws? How temperature not obeying vector laws?
Answer» what is vector laws? How temperature not obeying vector laws?

Discussion

4898.	A flood relief jet flying at 2 km height and moving at a speed of 200 m/s drops a food packet. A car is 1 km in front of the jet. If it starts from rest, with what constant acceleration car should be driven so as to catch the food packet? Take 'g' as 10 m /s²
Answer» A flood relief jet flying at 2 km height and moving at a speed of 200 m/s drops a food packet. A car is 1 km in front of the jet. If it starts from rest, with what constant acceleration car should be driven so as to catch the food packet? Take 'g' as 10 m /s²

Discussion

4899.	If density,accleration due to gravity g and frequency v are the basic quantities,find the dimension of force?
Answer» If density,accleration due to gravity g and frequency v are the basic quantities,find the dimension of force?

Discussion

4900.	On a 120 km track, a train travels the first 30 km with a uniform speed of 30 km/hr . How fast must the train travel the next 90 km so as to average 60 km/hr for the entire trip?
Answer» On a 120 km track, a train travels the first 30 km with a uniform speed of 30 km/hr . How fast must the train travel the next 90 km so as to average 60 km/hr for the entire trip?

Discussion

Explore topic-wise InterviewSolutions in .

What type of frequencies do bats use for echolocation?

27.When an object is vertically thrown downward from a certain height H.why do we take u =-u, a = -g, s = - H, v = -v? Even acceleration is negative. Why?

What do you mean by green house effect?

UV rays act on chlorofluorocarbons (CFCs) and release __________ which degrades the ozone layer in the stratosphere.

why a ray emerges parallel to the incident ray

32. Two bodies are in equilibrium when suspended in water from the arms of a balance. The mass of one body is 36 g and its density is 9 g/cc. If the mass of the other is 48 g, its density in g/cc is 1. 4/3 2. 3/2 3. 3 4. 5 Click here to view details:

calculate the energy spent in spraying a drop of mercury 1 cm radius into 10^{6 _{}}droplets all of same size. surface tension=35×10^{-3}N/m^2.

An object moves with an acceleration of 3ms2 when a force of 30 N is applied. The mass of the body is ___ kg.

A body is moving uniformly in a straight line with a velocity of 5 m/s. Find graphically the distance covered by it in 5 seconds.

What is mechanical strength

Question 8Water stored in a dam possesses(a) no energy(b) electrical energy(c) kinetic energy(d) potential energy

what is the difference between optimum speed and maximum speed during banking of roads? Also explain that at optimum speed the friction force is not required to produce centripetal force

The number of significant figures in the distance of one light year , 9.4605 × 10 15 m is

83. A solid sphere of radius R is placed on a smoothhorizontal surface. A horizontal force F is applied atheight h from the lowest point. For the maximumacceleration of centre of mass, which is correct?(1) h R(2) h=2R(3) h=0(4) Centre of mass has same acceleration ineach case

5 A piece of solid is embedded inside an ice block when floats in water.when ice melts completely,the level of water 1)remains same,if dsdw and 2) falls ,if ds>dw. HOW?

Difference between echo and reverberation?

What are the 2 factors affecting buoyant force

Find the energy KWh consumed in 10 hours by four devices of power 500?

Draw a graph for acceleration against time for a uniformly accelerated motion.How can it be used to find the change in speed in a certain interval of time?

If v=3 + ax, where a is a cons†an t then draw the acceleration Vs time graph andalso write the nature of graph.

Which of the following forces helps us walk on ground?

1. A uniform flexible chain of mass m and length l hangs in equilibrium over a smooth horizontal pin of negligible diameter. One end of the chain is given a small vertical displacement so that the chain slips over. The speed of chain when it leaves pin is

What is the distance travelled by a body and its displacement when it completes one revolution around a circular track with radius r?

An object thrown vertically upwards, rises to a maximum height of 10 m. What is the velocity with which it is thrown upwards? (Take g=9.8 m s−2)14

If a body travels very large distance compared to its size, then the body is considered to be a

why a cell always gives a smaller amount of current ?

What type of waves are generated by SONAR device fixed to a fishing ship ? (a) water waves (b) radio waves (c) sound waves (d) infrared waves

18.If acceleration a=4-4t/2,then find average acceleration for t=1 to 2 sec

The temperature at which a black body of unit area loses its energy at the rate of 1 joule/second is

A truck of mass 5000 kg is moving with a velocity of 20 ms−1. To avoid an accident, the driver applies brakes to stop the truck in 5 seconds. Calculate the force applied by the brakes in order to stop the truck in the given time using work-energy theorem.

If 250 J of work is done in sliding a 5 kg block up an inclined plane of height 4m. Work done against friction is

Consider the following table for an LTI system having an impulse response h(t). Input Output x(t) y(t) ddtx(t) −3y(t)+e−2tu(t)where, x(t)=2e−3tu(t−1)Then the impulse response h(t) of the system is

The value of resis†an ce determined by colour bands of a carbon resistor is 0.51 + 10% . Write the colours of bands in corect order.

a wire of given material having length I and area of cross section A has a resis†an ce of 4ohms .what would be the resis†an ce of another wire of the same material having length 1/2 and area of crossection 2A

A bus travelled the first one-third distance at the speed of 10 km/h, the next one-third at 20 km/h and the last one-third at 60 km/h. The average speed of the bus is :

The people in a bus are pushed backwards when the bus starts suddenly because of:

A thin rod of length f3 is placed along the optic axis of a concave mirror of focal length f such that its image which is real and elongated just touches the rod. The magnification is:

104.A car is approaching towards a stationary observer with the speed 10 m/s while blowing whistle of frequency f= 440 Hz. The frequency of whistle heared by observer is ( given speed of sound = 340)

Which type of colour did Thomson observed when he found electrons while cathode rays experiment?

Question 129(ii) The table shows the mass of the planets, the Sun and the Moon in our solar system. Order the planets and the Moon by mass, from least to greatest.

In myopic eye , when we stretch our eye muscles , why we can see far objects more clearer without spectacles?

A steel wheel of 600 mm diameter rolls on a horizontal steel rail. It carries a load of 500 N. The coefficient of rolling resistance is 0.3 . The force in N, necessary to roll the wheel along the rail is

In a fight, a man fires 50g bullets from a machine gun, each at a speed of 1.0 km/s. If he fires 20 bullets in 4 seconds, what average force does he exert against the machine gun during this period?

what is vector laws? How temperature not obeying vector laws?

A flood relief jet flying at 2 km height and moving at a speed of 200 m/s drops a food packet. A car is 1 km in front of the jet. If it starts from rest, with what constant acceleration car should be driven so as to catch the food packet? Take 'g' as 10 m /s²

If density,accleration due to gravity g and frequency v are the basic quantities,find the dimension of force?

On a 120 km track, a train travels the first 30 km with a uniform speed of 30 km/hr . How fast must the train travel the next 90 km so as to average 60 km/hr for the entire trip?