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

Not sure but may be photometal is the metal that can release electrons when a light of suitable frequency is incident on it (or shows photoelectric effect)...

1Thank You

ANSWER

What is walfer?

Posted by Tamanna Sharma 6 years ago

CBSE > Class 12 > Physics

3 answers

Yuvraj Singh 6 years ago

A wafer (also called a slice or substrate) is a thin slice of semiconductor, such as a crystalline silicon , used for the fabrication of integrated circuits and to manufacture solar cells.

1Thank You

Tamanna Sharma 6 years ago

Sorry it's a spelling error it's wafer not walfer ( semi conductors )

1Thank You

Riya Rana 6 years ago

In what context is it being refered as in here ?

1Thank You

ANSWER

Why a photo diode is operated in reverse bias connection?

Posted by Abhishek Sah 6 years ago

CBSE > Class 12 > Physics

2 answers

Riya Rana 6 years ago

In reverse biasing the depletion is wider so more amount of light can be captured plus to easily observe the changes in current with the change in intensity of the incident light.

1Thank You

Tamanna Sharma 6 years ago

Because in reverse bias it is easy to observe change in current with change in light intensity

1Thank You

ANSWER

How zener diode act as voltage regulator?

Posted by Abhishek Sah 6 years ago

CBSE > Class 12 > Physics

1 answers

Tamanna Sharma 6 years ago

When reverse bias voltage reaches the breakdown voltage, then there is a large change in current and after that just above breakdown voltage large change in the current is insignificant change in reverse bias voltage and use as a voltage regulator

1Thank You

ANSWER

On which principal does potentiometer work

Posted by Utpal . 6 years ago

CBSE > Class 12 > Physics

1 answers

Tamanna Sharma 6 years ago

Potential gradient: whena steady current is flows through a wire AB then there is a fall of potential along the wire fromA to B

1Thank You

ANSWER

ImportantDerivation of physics

Posted by Utpal . 6 years ago

CBSE > Class 12 > Physics

2 answers

Kunal Kumar 6 years ago

Electric dipole along axial and equatorial line, gauss theorem, electric potential, youngs double slit exp, etc

0Thank You

Raman Kant 6 years ago

Compound microscope

0Thank You

ANSWER

Which topics very important.

Posted by Himanshu Prasad 6 years ago

CBSE > Class 12 > Physics

1 answers

Ɽøⱨł₮ ₲Ʉ₱₮₳ 6 years ago

Current electricity ray optics wave optics magnetism

0Thank You

ANSWER

We are having doubt in physics can we ask question in this app??

Posted by Himanshu Prasad 6 years ago

CBSE > Class 12 > Physics

5 answers

Aditya Chauhan 6 years ago

Accha

1Thank You

Tamanna Sharma 6 years ago

We are welcoming you

1Thank You

Tamanna Sharma 6 years ago

No only you never ask questions here ????? l am just kidding of course you ask your's queries here at all time

0Thank You

Ankit Bishwakarma 6 years ago

Of course

0Thank You

Kanchan Choudhary Jat 6 years ago

Of course

0Thank You

ANSWER

Electric field intensity due to group of charges

Posted by Gagan Deep 6 years ago

CBSE > Class 12 > Physics

1 answers

Riya Rana 6 years ago

Gagan, electric field intensity at any point due to a group of charges is equal to the VECTOR sum of electric field intensities due to INDIVIDUAL charges.

0Thank You

ANSWER

Is Junction Transistor In CBSE 2019-20 Syllabus?

Posted by Shubhashish Ranjan 6 years ago

CBSE > Class 12 > Physics

3 answers

Ankit Bishwakarma 6 years ago

0Thank You

Shubhashish Ranjan 6 years ago

ThankYou ☺

1Thank You

Mahi D 6 years ago

1Thank You

ANSWER

Posted by Mahi D 6 years ago

CBSE > Class 12 > Physics

2 answers

Tamanna Sharma 6 years ago

What you want to ask

0Thank You

Mahi D 6 years ago

Three concentric spherical metallic shells A , B and C of radii a , b and c (a<b<c) have charge densities σ,−σandσ respectively . If the shells A and C are at the same potential then the relation between a , b and c is? I am unable to upload this question fully in ask questions section.maybe some issue is there.. Pls answer this here.

0Thank You

ANSWER

Posted by Mahi D 6 years ago

CBSE > Class 12 > Physics

2 answers

Riya Rana 6 years ago

Mahi you can write the question directly...

0Thank You

Mahi D 6 years ago

This question is not uploaded fully aven after writing the whole question in ask section.. can anyone tell what has gone wrong??

0Thank You

ANSWER

In exemplar ,it is given that electric field is continuous if there is no charge at that point and discontinuous if there is a charge present at that point, so logically if field is affected due to the charge presence then according to the relation F=qE ,force also have to affected by this. But we study force is not affected by the presence of other charge. Please explain if you have explanation for this .

Posted by Tamanna Sharma 6 years ago

CBSE > Class 12 > Physics

4 answers

Tamanna Sharma 6 years ago

Can you please explain this with the electric field as l mension in my query and l know superposition principle and my question is different

0Thank You

Vaibhav Srivastava 6 years ago

According to superposition principle force on a charge by the group of charges are the vector sum of the forces of all the charges. Now just think of a system of charges A and B. The force on A is due to charge B. If a charge C is put in the system then the net force on A will be the vector sum of the forces produced by the charges B and C but the force between A and B remains same. This way we can say that the force is a two body interaction and hence cannot be affected by the third body.

1Thank You

Riya Rana 6 years ago

Ohh yeah... Good question..

1Thank You

Tamanna Sharma 6 years ago

If you want to check it go for Q 1.9 in MCQ type ll in NCERT Exemplar

0Thank You

ANSWER

What is the weightage of theory and numericals in physics

Posted by Yakuza Shimatoro 6 years ago

CBSE > Class 12 > Physics

4 answers

Tamanna Sharma 6 years ago

For both of you I want to tell that more portion of paper is conceptual ,graphs and understanding based and pure numerical portion is less in board,go and check it on cbse site .

0Thank You

Shubhashish Ranjan 6 years ago

Wrong...There Is No Specific Weightage For Theory And Numerical Section But Be Prepared For More Numericals Because The Pattern Is Changed And There Must Be More Questions On Application.

1Thank You

Balram Sharma 6 years ago

No you are wron

1Thank You

Tamanna Sharma 6 years ago

70% theory and 30% numerical

1Thank You

ANSWER

I want a list of all deleted topics from CBSE syllabus this year 2019 please list them all chapter wise

Posted by Ankit Beniwal 6 years ago

CBSE > Class 12 > Physics

1 answers

Shubhashish Ranjan 6 years ago

Go Through Official Website Of CBSE.☺

0Thank You

ANSWER

I know it's a silly question but l am just confused in it. Q: we know current is a scalar(more accurately tensor) quantity and area is also a scalar quantity, then how current density is a vector quantity. Please clear this confusion??

Posted by Tamanna Sharma 6 years ago

CBSE > Class 12 > Physics

9 answers

Tamanna Sharma 6 years ago

What are you saying divya it's totally crazy

0Thank You

Divya Shrivastav 6 years ago

area is a vector quantity and it is independent from its surface

1Thank You

Riya Rana 6 years ago

No area is not a vector quantity it actually is a scalar quantity but we make it vector by using UNIT VECTOR concept.

2Thank You

Tamanna Sharma 6 years ago

Shubhashish all times area is not a vector in some cases we consider it as area vector,but you don't say that area is a vector quantity. REASON inorder to consider area as a vector because of the orientation factor and for simplification we use projection area means resolved form of area in the direction of the another quantity like field. But here l want to ask a small integral area not consider the whole area so how at this time we can say that J is a vector quantity, we always we study it as a vector.

1Thank You

Mahi D 6 years ago

We consider area vector here which is normal to the plane so area is a vector and current is scalar.

0Thank You

Shubhashish Ranjan 6 years ago

Area Is A Vector Quantity. ☺

1Thank You

Shubhashish Ranjan 6 years ago

Area Is A Vector Quantity.☺

0Thank You

Tamanna Sharma 6 years ago

In many books there is no explanation, they directly write it as a vector quantity.,so if you know any website ,where this is well explained, please share it with me.

0Thank You

Riya Rana 6 years ago

Refer to unit vector from class 11 it was well explained there if you remember.

1Thank You

ANSWER

If the charge is placed on the gaussian surface, is it will be consider in finding out flux.explain with a suitable reason.

Posted by Tamanna Sharma 6 years ago

CBSE > Class 12 > Physics

4 answers

Tamanna Sharma 6 years ago

But why we don't consider this charge .what is the reason behind this ,please ask this question to your teacher as l asked this question to my physics teacher 6 times but except 1 time ,each time ,he says shut up and don't disturb the class.

1Thank You

Mahi D 6 years ago

Hey Tamanna , I looked for this in sl arora ... According to defination, gaussian surface is a closed surface enclosing a charge but it is written nowhere that if the charge is on gaussian suface then it is not considered . I could tell this much only.. if you clear this confusion then please tell the answer here also.

1Thank You

Tamanna Sharma 6 years ago

But my teacher told me that charge must be inside this gaussian surface, not on surface can you please, verify my query, like this type problem given in any book.

1Thank You

Mahi D 6 years ago

Yes it will be considered. We imagine a gaussian surface so that the the point at which flux is to be calculated lies on it. You can see the application of gauss theorem . We construct gaussian surfaces ourselves to find flux on a given point.

1Thank You

ANSWER

Can a polarized light make again an unpolarized light. If yes, then suggest a method.

Posted by Tamanna Sharma 6 years ago

CBSE > Class 12 > Physics

2 answers

Tamanna Sharma 6 years ago

I don't understand ,which angle change or is there any specific device to do this ,please tell me so that this will enhance my understanding.

0Thank You

Riya Rana 6 years ago

Yes by change in angles

1Thank You

ANSWER

Diode and zenner diode with characteristics

Posted by Gaurav Shekhar 6 years ago

CBSE > Class 12 > Physics

1 answers

Riya Rana 6 years ago

Zener diode's main characteristic is to act as a volatge regulator. It acts as voltage regulator by supplying excess heavy current and excess voltage across the Rs resistor when the incoming fluctuating volatge exceeds the breakdown voltage.

1Thank You

ANSWER

What is the force b/w parallel plate capacitor?

Posted by Bhaskar Rij Rij 6 years ago

CBSE > Class 12 > Physics

1 answers

Riya Rana 6 years ago

E=sigma/E●. F=q×E so... F=sigma×q/E●

0Thank You

ANSWER

Why they use only magnin in preparation of...magnetic wires in d magnetic bridges??

Posted by Ayaan Ali ?? 6 years ago

CBSE > Class 12 > Physics

1 answers

Riya Rana 6 years ago

Magnin is a alloy. Alloys have high resistivity and very low temperature coefficient. Magnin is used in the magnetic wires because it the ONLY alloy that is completely independent of temperature (lowest temperature coefficient).

0Thank You

ANSWER

Please tell me the impt topics from ch-14 semiconductor for preparation of boards?

Posted by Sarthak Jain 6 years ago

CBSE > Class 12 > Physics

1 answers

Riya Rana 6 years ago

Semiconductors is coming for 7 MARKS in BOARDS it is a highly important chapter apparently ( even more than electrostatics ) and when it comes to topics you should do entire chapter thoroughly but most importants are DIODES (all four types) and HALF WAVE AND FULL WAVE RECTIFIER !!

0Thank You

ANSWER

Tow wireof copper and other of manganin have same resistance and equal length.which wire is thicker and why

Posted by Ravi Verma 6 years ago

CBSE > Class 12 > Physics

1 answers

Madan Kumar 6 years ago

Manganin wire is thicker than copper wire Due to resitivity is directly proportional to area, therefore. Area of manganin is greater than area of copper. So, it is thicker.

0Thank You

ANSWER

Microscope and telescope derivation at near point and infinity

Posted by Chamba Gyasto 6 years ago

CBSE > Class 12 > Physics