CBSE > Class 11 > Physics | CBSE Board | Homework Help

Ask questions which are clear, concise and easy to understand.

Ask Question

What is Hooke's law??????

Posted by Cute Princess 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Ɽøⱨł₮ ₲Ʉ₱₮₳ 7 years, 2 months ago

Hooke's law state that stress is directly proportional to strain

0Thank You

Lavanya ❤️? 7 years, 2 months ago

It states that within the limit of elasticity, the stress induced (σ ) in the solid due to some external force is always in proportion with the strain

1Thank You

ANSWER

Why srain is unit less????

Posted by Cute Princess 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Lavanya ❤️? 7 years, 2 months ago

Strain has less unit because it is a ratio of two similar quantities

0Thank You

Pragati Gola 7 years, 2 months ago

Because numerator and denominator both have same units which cancel out.e.g. volumetric strain =dv/v=m^3/m^3

1Thank You

ANSWER

Why strees is unit less?

Posted by Cute Princess 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Cute Princess 7 years, 2 months ago

Srry my question is wrong

0Thank You

Ankit Singh 7 years, 2 months ago

Stress-Strain Curves. The tensile stress on a material is defined as the force per unit area as the material is stretched. ... stress: The units of stress are the same as those of pressure.We will use pascals, Pa, as the units for the stress

1Thank You

ANSWER

What is stress and strain??????

Posted by Cute Princess 7 years, 2 months ago

CBSE > Class 11 > Physics

7 answers

Cute Princess 7 years, 2 months ago

Yes it's very useful Ankit Thank u so much

1Thank You

Ankit Singh 7 years, 2 months ago

In simple language

0Thank You

Ankit Singh 7 years, 2 months ago

Great answer Darshana

0Thank You

Ankit Singh 7 years, 2 months ago

The ratio of extension to original length is called strain it has no units as it is a ratio of two lengths measured in metres. Strain = extension/ length hope this will help u

2Thank You

Ankit Singh 7 years, 2 months ago

The stress applied to a material is the force per unit area applied to the material. The maximum stress a material can stand before it breaks is called the breaking stress or ultimate tensile stress. Stress= Force/area stress = stress measured in Nm-2 or pascals (Pa) F = force in newtons (N) A = cross-sectional area in m2

1Thank You

Ʌɐpɐʎ Ɐuɐɥsɹɐp . 7 years, 2 months ago

✴️ The internal restoring force acting per unit area of a deformed body is called stress. ✴️ The fractional change in configuration is called strain.

1Thank You

Aman Kumar 7 years, 2 months ago

Stress:- The restoring force acting per unit area...........Strain:- The ratio of change in dimension and initial dimension...

1Thank You

ANSWER

2 vibrating strings of the same material but lengths L and 2L have radii 2r and r respectively. They are stretched under the same tension. Both the strings vibrate in their fundamental modes, the one of length L with frequency ν1 and the other with frequency v2. what is the ratio of v1/v2..... ??

Posted by Ʌɐpɐʎ Ɐuɐɥsɹɐp . 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Ankit Singh 7 years, 2 months ago

But it is a nice question

0Thank You

Ankit Singh 7 years, 2 months ago

Please answer mujhe nahi aata

0Thank You

ANSWER

Chapter:- Motion in a straight line Position of particle is directly proportional to time. What is the nature of its motion?

Posted by Arvind Bhardwaj 7 years, 2 months ago

CBSE > Class 11 > Physics

0 answers

ANSWER

Do questions comes from physical world in main exam?

Posted by Garv Raj 7 years, 2 months ago

CBSE > Class 11 > Physics

3 answers

Garv Raj 7 years, 2 months ago

Thats the problem nah. I m an IIt aspirant i have joined a non attending cbse school. So i dont know whats going on thats why i asked you all. Bs passing marks le aana hai 11th me.?? Chor hi deta hu iss chapter ko hardly 2 marks ka ques. aata hoga iss seh.

1Thank You

Priya Dharshini ? 7 years, 2 months ago

Did they teach this chapter in school? If they taught it will surely come

1Thank You

Priya Dharshini ? 7 years, 2 months ago

I think so this chapter is removed from syllabus. Questions will not be asked in main exams. But now it depends upon ur school

2Thank You

ANSWER

Calculatr the temperature in k of a perfectly black body whicj radiates energy at the rate of w/cm

Posted by Suvasish Ghosh 7 years, 2 months ago

CBSE > Class 11 > Physics

0 answers

ANSWER

Why do we use lens combination in optical instruments ?write an expression for the effective focal length of two thin lenses placed in contact coaxially with each other

Posted by Rohit Kumar 7 years, 2 months ago

CBSE > Class 11 > Physics

0 answers

ANSWER

Derive an expression for the rise of capillary tube in term of force of surface tension

Posted by Jaid Khan 7 years, 2 months ago

CBSE > Class 11 > Physics

0 answers

ANSWER

Can u revisit the important questions of this subject

Posted by Peerzada Nooruleman 7 years, 2 months ago

CBSE > Class 11 > Physics

1 answers

Priya Dharshini ? 7 years, 2 months ago

U will get in this app important questions and practice solved and unsolved questions of ncert

2Thank You

ANSWER

Which physics,s book best for class 12 preparation

Posted by Satya Yadav 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Akanksha Kumari? 7 years, 2 months ago

Hc verma is also a good book for 12th in my view

0Thank You

Prangana Phukon 7 years, 2 months ago

NCERT ( the heart of board physics)

0Thank You

ANSWER

Work energy therom

Posted by Rudraksh G 7 years, 2 months ago

CBSE > Class 11 > Physics

3 answers

Ankit Singh 7 years, 2 months ago

The Work-Energy Theorem. The principle of work and kinetic energy (also known as the work-energy theorem) states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle.

4Thank You

Priya Dharshini ? 7 years, 2 months ago

Work done by all force is equal to change in kinetic energy.

1Thank You

Lavanya ❤️? 7 years, 2 months ago

IWork energy therom states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle

0Thank You

ANSWER

What is the pressure on a swimmer 10m below the surface of a lake

Posted by Kishore Kumar Das Mohapatra 7 years, 2 months ago

CBSE > Class 11 > Physics

1 answers

Lavanya ❤️? 7 years, 2 months ago

Let Pa be atmospheric pressure P=Pa +dgh ( d is density of water) P=1.05×10^5×1000×9.8×10 P=1.99×10^5pa P=2 atm (approximately) Therefore the pressure is 2 atm

0Thank You

ANSWER

Explain the working of a refrigerator as a heat pump.

Posted by Kunal Gupta 7 years, 2 months ago

CBSE > Class 11 > Physics

1 answers

Yogita Ingle 7 years, 2 months ago

It works on principle which is reverse of a heat engine.
In refrigerators we have 2 bodies lower temperature (cold) body which is freezer and higher temperature (hot) body which is surroundings.
It takes heat from the cold reservoir and then some work is done on the refrigerator and then the amount of heat is transferred to heat reservoir.
Let Q₂ be the takes from the cold reservoir, W is the work done on the system and then releases Q₁ amount of heat to the hot reservoir.
Mathematically Q₂+ W=Q₁

Heat Pump: In a heat pump heat is supplied into system when the surroundings are cold.

0Thank You

ANSWER

Why CV is less than CP

Posted by Shakti Rathore 7 years, 2 months ago

CBSE > Class 11 > Physics

1 answers

Yogita Ingle 7 years, 2 months ago

Cp (specific heat at constant pressure)
Cv (specific heat at constant volume)
When a gas is heated at constant volume,no external work is done and so the heat supplied is consumed only in increasing the internal energy of a gas.
But if the gas is heated at constant pressure , the gas expands against the external pressure so does some external work.In this case the supplied heat is used up in increasing the internal energy of the gas and in doing some external work .
Since the internal energy is depends only on temperature,for the same rise of temperature the internal energy of a mass of a gas will increase by the same amount whether the pressure or volume remains constant.But since external work is additionally done for constant pressure than at constant volume to produce the same rise in temperature of the gas. Above is the reason for Cp is greater than Cv.

2Thank You

ANSWER

Relation between angular veocity and linear velocity?

Posted by Arun Kamboj 7 years, 2 months ago

CBSE > Class 11 > Physics

1 answers

Avantika Tayal 7 years, 2 months ago

w=r×v

2Thank You

ANSWER

why zeroth law is named so?????

Posted by Yakshi Baliyan 7 years, 2 months ago

CBSE > Class 11 > Physics

4 answers

Ankit Singh 7 years, 2 months ago

It is called the "zeroth" law because it came to light after the first and second laws of thermodynamics had already been established and named, but was considered more fundamental and thus was given a lower number — zero. Hope this will help u yakshi

1Thank You

Yogita Ingle 7 years, 2 months ago

The zeroth law is so named because it logically precedes the first and second laws of thermodynamics.
The zeroth law of thermodynamics is the basis for temperature measurement of a body or object. It defines the exchange of heat as well as defines the temperature. The law deals with the concepts used for designing the thermometer.

1Thank You

Lavanya ❤️? 7 years, 2 months ago

It is called the zeroth law because it came to light after the first and second laws of thermodynamics

1Thank You

Ayushi Ayushi 7 years, 2 months ago

1Thank You

ANSWER

Define Pascal's law???

Posted by Lavanya ❤️? 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Lavanya ❤️? 7 years, 2 months ago

Thank u

2Thank You

Ayushi Ayushi 7 years, 2 months ago

Pascal's law basically states that any pressure applied to a fluid inside a closed system will transmit that pressure equally in all directions throughout the fluid. This law is the basic principle that causes hydraulic power in heavy construction machines to work. A hydraulic lift for automobiles is an example of a force multiplied by hydraulic press, based on Pascal's principle.

2Thank You

ANSWER

What is the phase difference between two nearest crest and trough

Posted by Ram Pandey 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Gaurav Seth 7 years, 2 months ago

The linear distance between two successive crests is equal to one wavelength.
The phase difference corresponding to two successive crests is equal to 2 pi radians (or) 360 degrees.

1Thank You

Kashish Mehta 7 years, 2 months ago

2π

0Thank You

ANSWER

What is Tensile stress or longitudinal strain

Posted by Yadav Suraj 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Yogita Ingle 7 years, 2 months ago

Longitudinal strain: If the deforming force produces a change in length alone, the strain produced in the body is called longitudinal strain or tensile strain.

Tensile Stress: If the stress applied causes an increase in the body’s length because of the force the stress is termed as tensile stress.

0Thank You

Ram Pandey 7 years, 2 months ago

They both are same meaning

2Thank You

ANSWER

Lens formula

Posted by Mitra Shukla 7 years, 2 months ago

CBSE > Class 11 > Physics

1 answers

Shatayu Ganvir 7 years, 2 months ago

1/v - 1/u =1/f

2Thank You

ANSWER

Calculate the critical angle for glass air interface, if a ray of light incidence in air on the surface is deviated through 15° when its angle of incidence is 40°. (Hr. Board 2009)

Posted by Saba Elias 7 years, 2 months ago

CBSE > Class 11 > Physics

3 answers

Ankit Singh 7 years, 2 months ago

Nice Answer Nancy

1Thank You

Nancy Rajput 7 years, 2 months ago

=>critical angle be ic. =>sinic= 1/ u where u is the refractive index of glass. => sin i / sin r =u i = 40° =>r = 40 - 15 = 25° => u = sin 40 / sin 25 => u = 1.521 = >sinic= 1/ 1.521 => ic=> sin-1(0.657) =41.11°

2Thank You

Nancy Rajput 7 years, 2 months ago

41.11o

1Thank You

ANSWER

What is optical fibres?

Posted by Saba Elias 7 years, 2 months ago

CBSE > Class 11 > Physics

2 answers

Ankit Singh 7 years, 2 months ago

An optical fiber is a thin fiber of glass or plastic that can carry light from one end to the other. The study of optical fibers is called fiber optics, which is part of applied science and engineering. Optical fibres have become very important in high-speed communications, such as cable TV and high-speed broadband services. Information, in the form of pulses of light, is sent down bundles of optical fibres. Fibre optic cables are able to carry more signals than traditional copper cable telephone lines. Hope this will help u saba ??

2Thank You

Nancy Rajput 7 years, 2 months ago

Optical fibers are made of glass. These are glass fibers. Now for fiber optic communication glass fibers are simply not enough they have to be specially built for total internal reflection (TIR). To achieve TIR the optical fiber is given an outer layer having a lower refractive index called cladding and the central part of the glass fibre is called core.

3Thank You

ANSWER

A point source of light is place 4 m below the surface of water of refractive index 5/3 . The minimum diameter of disc which should be placed over the source on the surface of water to cut off all light coming out of water is ( mu=5/3)

Posted by Saba Elias 7 years, 2 months ago

CBSE > Class 11 > Physics

6 answers

Ʌɐpɐʎ Ɐuɐɥsɹɐp . 7 years, 2 months ago

tnx.. ?✌️

2Thank You

Ankit Singh 7 years, 2 months ago

Nice answer darshana

1Thank You

Ʌɐpɐʎ Ɐuɐɥsɹɐp . 7 years, 2 months ago

OK then,, here it is ⤵️ ➡️ sin i = 1/μ = 3/5.......... ➡️tan i = 3/4= r/4.. by solving this we get radius = 3 m.... now we know that diameter =2×radius.. so,,,, diameter =2×3=6m....hope you understand.. ✌️

3Thank You

Saba Elias 7 years, 2 months ago

Yah... its right give me the full solution

0Thank You

Ʌɐpɐʎ Ɐuɐɥsɹɐp . 7 years, 2 months ago

if it is correct then I can give full solution of it..

1Thank You

Ʌɐpɐʎ Ɐuɐɥsɹɐp . 7 years, 2 months ago

answer may be 6m...

1Thank You

ANSWER

if the satellite is stopped suddenly in its orbit and allowed to fell freely on to the earth. Find the speed with which it hits the surface of the earth.

Posted by Yatin Singh 7 years, 2 months ago

CBSE > Class 11 > Physics

6 answers

Nishita Tomar 7 years, 2 months ago

this app is updated according to new syllabus..

0Thank You

Aman Kumar 7 years, 2 months ago

Wo toh hum jante hai...bus thoda likhne wale k muhh se sunna chahte the...

0Thank You

Ʌɐpɐʎ Ɐuɐɥsɹɐp . 7 years, 2 months ago

sub Google ki den hai... ?? itna v ni samjhte... ???

0Thank You

Aman Kumar 7 years, 2 months ago

And haan update this app according to new syllabus...??

0Thank You

Aman Kumar 7 years, 2 months ago

Gaurav ji...etna lamba answer laate kaha se hai app..???

0Thank You

Gaurav Seth 7 years, 2 months ago

The question is incomplete.

Q. A satellite is moving Only a circular orbit around the earth Again a height 6400km if the satellite Is suddelny stopped in its orbit and allowed to fall freely towards earth find the speed with which it hits the surface of the earth.

<hr />

Ans.

Height of the satellite from the surface of Earth = H = 6400 km.
Radius of Earth = R = 6400 km.
Mass of Earth = M.
G = Universal Gravitational constant.

Initial KE = 0. Speed = 0.
Gravitational potential energy of the satellite at height 6400 km
PE1 = - G M m/(H+R) = - G M m/ (2R)
= - (G M/R²) * (mR/2)
= - m g R / 2 , as gravity g on Earth's surface = GM/R²

This potential energy on the surface of Earth:
PE2 = - GMm/R = - (GM/R²) × (mR)
= - m g R

Potential Energy lost = PE1 - PE2
ΔPE = m g R/2

Kinetic energy gained = ΔKE = 1/2 m v²
1/2 m v² = m g R/2
v² = g R
v = √[g R]
= √[9.81 × 6400,000] m/s
v = 7923.64 m/s. = 28, 525 km/hr

2Thank You

ANSWER

What is a viscosity?

Posted by Piyush Kumar Pradhan 7 years, 2 months ago

CBSE > Class 11 > Physics

3 answers

Nancy Rajput 7 years, 2 months ago

Viscosity is the measure of internal friction of a liquid.This friction arises between different layers of a liquid and offers resistance to the flow of the liquid.Greater is the friction, greater is the amount of force required to cause the movement of liquid.Highly viscous fluids have more fraiction than less viscous fluids.The SI units of viscosity are Kg/ms or Pa s.

5Thank You

Archit Singh 7 years, 2 months ago

Molecular force of attraction between the molecules of a fluid

2Thank You

Gaurav Seth 7 years, 2 months ago

Viscosity refers to the resistance to the flow of liquid arising as a result of the internal friction within the layers as they pass over other layer.

3Thank You

ANSWER

Dimensions of stress

Posted by Gauranga . 7 years, 2 months ago

CBSE > Class 11 > Physics