CBSE > Class 12 > Physics | CBSE Board | Homework Help

Electric field is reduced due to insertion of dielectric because inside the dielectric an electric field is induced in the direction opposite to external electric field and this partially cancels the external electric field.

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ANSWER

Define dielectric constant

Posted by Piyush Khanna 7 years, 4 months ago

CBSE > Class 12 > Physics

2 answers

Priyanka Rana 7 years, 4 months ago

Dielectric constant is defined as the electric field in vaccum to the electric field in medium . It is denoted be K . The value of k for metals is infinite

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Pratibha Ydv 7 years, 4 months ago

It is the ratio of electrostatic force b/w two charges in vaccume/air to the electrostatic force b/w two charges in any medium placed at same distance. And it is denoted by K.

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ANSWER

An alpha particle is placed on a table at rest and a person moves with velocity 50m/s along a straight line slightly away from table observes what? Only electric field Only magnetic field Both None of these

Posted by Isha Taneja 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Hassanain Akram 7 years, 4 months ago

He observes electric field only Bcz stationary particle donot produce magnetic field.

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ANSWER

If an electron is falling downwards in presence of a uniform magnetic field towards north then in which directio it will get deflected?

Posted by Isha Taneja 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Sweety Sweety 7 years, 4 months ago

It will deflect toward south

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ANSWER

If magnetic moment of a current loop of radius Ris Mthen find out magnetic field strength at its centre.

Posted by Isha Taneja 7 years, 4 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

A potetial difference of 10 volt is applied a conductur of resistence 1kohm find no. of electron flowing through a conductor in 5 min.

Posted by Yashodeep Matkar 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Rahul Sharma 7 years, 4 months ago

1.875×10^19

1Thank You

ANSWER

Why the short focal length of eye piece and objective lens are taken to construct compound microscope

Posted by Thejaswini Chirnalli Mattad 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Thejaswini Chirnalli Mattad 7 years, 3 months ago

Send answer for this guys

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ANSWER

How i study 3 hrs a day

Posted by Nikhil Pal 7 years, 4 months ago

CBSE > Class 12 > Physics

2 answers

Kiara Khurrana 7 years, 4 months ago

plz dont study becoz books aapka itna aaheshan nahi jhel paayega

1Thank You

Abhat Singh 7 years, 4 months ago

By making TIME TABLE

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ANSWER

Tangent law proof

Posted by Aamir Khan 7 years, 4 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

A Electron travelling in positive x direction and force action in y direction .what is direction of magnet field

Posted by Prabhjot Singh 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Bharvi Dani 7 years, 4 months ago

Using Fleming's Right hand rule direction of magnetic field is mutually perpendicular to both of them. Not sure about this

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ANSWER

Why ac current can pass through capacitor but dc current can not????

Posted by Rohit Singh 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Sansar Sumra 7 years, 4 months ago

For ac frequency is finite so opposition offered bycapacitor is small as Xc=1/C2π(frequency) Xc= 1/large value (finite) so ac can flow from capacitor as Xc is small for ac. For dc frequency is zero so Xc= 1/C2π[0] Xc=1/0=infinite Xc becomes infinite for dc so dc can not flow from capacitor . Capacitor block dc.

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ANSWER

Cocave refracting surface Rare to denser Virtual image

Posted by Ashok Kumar 7 years, 4 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

What is 1 Faraday. Explain?

Posted by Drbn N 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Sweety Sweety 7 years, 4 months ago

C=1Q/1V...

2Thank You

ANSWER

What's is the unit of current

Posted by Priya Singh 7 years, 4 months ago

CBSE > Class 12 > Physics

4 answers

Priyanka Rana 7 years, 4 months ago

Ampere

0Thank You

Muskan Verma 7 years, 4 months ago

Ampere or coulomb /sec

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Aryan Jha 7 years, 4 months ago

Ampere is the unit of current

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Unnati Verma. Unnati Verma. 7 years, 4 months ago

Ampere is the unit of current

2Thank You

ANSWER

Why do we always use a positive test charge

Posted by Abd Fan 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Sweety Sweety 7 years, 4 months ago

Because if we take big charge then it can affect the system that we have maimtained

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ANSWER

A metallic wire coil is stationary in non uniform magnetic field . what is the EMF induced in the coil?

Posted by Simranjot Kaur 7 years, 4 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

What is super conductor ? Which are the 2 properties,a material should have to behave as a super conductor

Posted by Thejaswini Chirnalli Mattad 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Drbn N 7 years, 4 months ago

Superconducters are the substances which allow electricity to pass through them without any resistance or decrese in electricity. 1. The substance should have zero resistivity 2. This happens only at certain temperature for different substances

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ANSWER

Write the colour sequence of the resistor of resistance 100ohm +/-10%

Posted by Thejaswini Chirnalli Mattad 7 years, 4 months ago

CBSE > Class 12 > Physics

4 answers

Thejaswini Chirnalli Mattad 7 years, 4 months ago

It's wrong

1Thank You

Muskan Verma 7 years, 4 months ago

First it should be written as 10x 10to the power 1+-10% then colour sequence is brown black brown silver

0Thank You

Sakshee Kumari 7 years, 4 months ago

Brown black brown gold

0Thank You

Pratibha Ydv 7 years, 4 months ago

Black brown red silver Is it right or wrong plzz tell me also

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ANSWER

Two electric bulbs one of 200volt 40 wattand other is 200volt 100 watt are connected in a house wiring circuit

Posted by Arti Sharma 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Mohit Sepat 7 years, 4 months ago

Complete ur question

2Thank You

ANSWER

If a charged particle enters a magnetic field at angle 30°and leaves at angle 60° hen what is the effect on its speed?

Posted by Isha Taneja 7 years, 4 months ago

CBSE > Class 12 > Physics

1 answers

Lipak Mohapatra 7 years, 4 months ago

The speed decreases.

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ANSWER

Can permeability of a medium be less than 1?

Posted by Isha Taneja 7 years, 4 months ago

CBSE > Class 12 > Physics

2 answers

Isha Taneja 7 years, 4 months ago

But i think that it is the case of relative permeability but i m asking about any medium

0Thank You

Ravi Yadav 7 years, 4 months ago

Yes in case of diamagnetic substances

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ANSWER

image formation by lens

Posted by Afza Parveen 7 years, 4 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Can like charge be attracted or not ?

Posted by Hassanain Akram 7 years, 4 months ago

CBSE > Class 12 > Physics

3 answers

Lipak Mohapatra 7 years, 4 months ago

When mass as well as charge is very much greater of a body in comparison to other then the electrostatic force of attraction behaves as gravitational force as the lines of force of the greater one have larger magnitude and enclose the whole electric field of the smaller one.

1Thank You

Sweety Sweety 7 years, 4 months ago

Yes , they can attract when one charge in them have less charge in comparision to other

1Thank You

Øshèen Gray 7 years, 4 months ago

Generally like charges repel each other but in some cases like charges may attract like, when ,2 bodies moving parallel 2 each other with same velocity.....

6Thank You

ANSWER

What will happen when emitter is in reverse bias and collector is in revese bias

Posted by Tanu Kamboj 7 years, 4 months ago

CBSE > Class 12 > Physics

3 answers

Ravi Yadav 7 years, 4 months ago

This is not possible because if both are revers biased then transmitter will not work,and it is not useful

1Thank You

Chirag Solanki 7 years, 4 months ago

if emitter is in reverse bias and collector is in reverse bias then emitter terminal not work

1Thank You

Anjana Sherawat 7 years, 4 months ago

Then trasmiter will not work

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ANSWER

calculate the speed of light in a medium whose critical angle is sin 30

Posted by Ayushi Singh 7 years, 4 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

if I/t graph of dc which have peak value =a is overlapped on graph of ac which have peak value=b then find the Irms of overlapped graph

Posted by Bhawna Choudhary 7 years, 4 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Why there is induction of current in the coil when bar magnet is kept near the coil

Posted by Pranav Sharma 7 years, 4 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Why does bluish colour predominate in a sky

Posted by Dinesh Kumar 7 years, 4 months ago

CBSE > Class 12 > Physics

2 answers

Pranav Sharma 7 years, 4 months ago

But at the time of sunset the sun is at horizon. The partial distance between us and the sun is much more so red light is more visible to us as it has more wavelenght blue light is not as much visible at that time as it scatter in the sky but red light do not scatter in the sky so at the time of sun set red light is predominating

0Thank You

Pranav Sharma 7 years, 4 months ago

Blue light has the shortest wavelength and the highest frequency but red light has the longest wavelength and smallest frequecy. So an i day time the partial distance between the sun and us is small and blue light due to its high frequency scatter much more than the red light. So sky seems to be blue

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ANSWER

Plot the graph for change in flux, emf ,force with respect to time with the conducting rod PB of resistance R of length L Moved frely tooo and fro with speed v on a rectangular conductor placed in magnetic field

Posted by Ravi Gupta 7 years, 4 months ago

CBSE > Class 12 > Physics