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Can torque on dipole be negative?

Posted by Gauraang Parashar 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Sourin Roy 7 years, 6 months ago

torque is a vector quantity so the sign(+/-) is actually used to determine the direction of the torque acting while the magnitude is taken with a modulus. But if u don't distinguish direction and magnitude separatly than calculate by taking the sign of the charge and so torque can be overall negative but its magnitude can't be negative

ANSWER

Most easy chapter of phys...

Posted by Sharma Saabh 7 years, 6 months ago

CBSE > Class 12 > Physics

7 answers

Aarti No 7 years, 6 months ago

Communication system and em waves

Aayisha Azeez 7 years, 6 months ago

Optics

Abhishek Soni 7 years, 6 months ago

Magnetism and ac

Benedict Sabu 7 years, 6 months ago

Em waves

Priya Prakash S 7 years, 6 months ago

Electrostatics

Aashish Kumar 7 years, 6 months ago

Photoelectric effect

Jin Kazama 7 years, 6 months ago

Optics

ANSWER

What do you mean by dipoles in molecules???

Posted by P Bhardwaj 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Sparsh Anand 7 years, 6 months ago

Dipole means two different poles positive and negative aapear due to electronegativity difference.eg HCl

ANSWER

Pnp or npn which transistor is important??

Posted by Priya Prakash S 7 years, 6 months ago

CBSE > Class 12 > Physics

4 answers

Sharma Saabh 7 years, 6 months ago

Important

Sharma Saabh 7 years, 6 months ago

Yes both r

Radhika Tyagi 7 years, 6 months ago

Both r important

Ishika Tanwani 7 years, 6 months ago

Yes

ANSWER

What is galvanometer?

Posted by Daphney Lang 7 years, 6 months ago

CBSE > Class 12 > Physics

5 answers

Ankita Vats 7 years, 6 months ago

Used to detect small current.

Aashish Kumar 7 years, 6 months ago

It is a device which is used to detect and measure the current

Sharma Saabh 7 years, 6 months ago

It is a device which gives u thevdirection of flowbif current

Ishu Chouhan 7 years, 6 months ago

It is a device which is used to measure small current.

Benedict Sabu 7 years, 6 months ago

It is a device used to detect the presence of current in a cicuit.

ANSWER

Why frequency of a DC is zero

Posted by Jin Kazama 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Benedict Sabu 7 years, 6 months ago

DC is a syeady current. It is not time varying. Hence its frequency is zero.

ANSWER

Graph of resitivity vs temperature for metals with exaplanation.

Posted by Dipti Yadav 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Jin Kazama 7 years, 6 months ago

Yha nhi banta hai

ANSWER

Difference between Gauss theoram of magnetism and electrostatics??

Posted by Yuthika Yadav 7 years, 6 months ago

CBSE > Class 12 > Physics

3 answers

Kalindi Yadav 7 years, 6 months ago

Your Welcome

Yuthika Yadav 7 years, 6 months ago

Thanks Garima

Kalindi Yadav 7 years, 6 months ago

Gauss law of magnetism states that the divergence of a magnetic field is zero whereas divergence of electric field is not zero. This suggests that magnetic monopole does not exists. Divergence of a physical quantity gives us the idea about diverging nature of a physical quantity. Now, since magnetic field lines are in closed loop, therefore, divergence of magnetic field comes out to be zero.

ANSWER

Doppler's effect

Posted by Shivanshu Yadav 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Kalindi Yadav 7 years, 6 months ago

Doppler Effect Light: The apparent change in the frequency due to relative motion between the source and observer is called Doppler Effect.

ANSWER

Plot a graph of potential energy of two nucleons as a function of their separation

Posted by Man Amne 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Radhika Tyagi 7 years, 6 months ago

Yha graph ni bnta

ANSWER

In communiction system channel acts as the physical medium for connecting transmitter and reciever. In case of cell phones while talking, can air act as a channe ?

Posted by Ritika Kapoor 7 years, 6 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

My question from wave optics "why photo electric effect no basis of wave nature of light "

Posted by Hari Tiwari 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Kalindi Yadav 7 years, 6 months ago

There are two main aspects of experimental results which cannot be explained by wave theory. If light is wave then its energy increases as we increase the intensity of the wave, but this increases only the number of electrons emitted but does not increase the energy of the electron. Secondly if electrons absorbs the energy of the wave, the emission of the electron must be delayed with respect to the instance light falls on the substance, but it is immediate. Lastly, photon theory of light is just not what you state, "And a "photon" is simply a measure of energy of an electromagnetic wave with a certain wavelength or frequency." the model is completely different. In a a wave model electron has to oscillate as per the oscillating electric field and gain enough energy and then get out. In a photon model which is not just another particle model but it is a quantum model emphasizing duality at the fundamental level. According to it light consists of particles each with energy "hf". [Note that energy is particle aspect and frequency is wave aspect. This particle meets the electron and itself gets vanished, giving all its energy in one shot process to the electron.

ANSWER

Alpha particles

Posted by Chhuana Tea 7 years, 6 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Alpha particle

Posted by Chhuana Tea 7 years, 6 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

If in nature ther may not be an element for which the principal quantum number n>4, then the total possible number of element will be

Posted by Shnaya Kashyap 7 years, 6 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Is transistor as amplifier in 2018 syllabus????

Posted by Priya Prakash S 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Radhika Tyagi 7 years, 6 months ago

Yup

ANSWER

Is transistor as switch in 2018 syllabus???

Posted by Priya Prakash S 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Radhika Tyagi 7 years, 6 months ago

No

ANSWER

Deduse ohm's law from elementary ideas and hence write an expression for resistance and resistivity.

Posted by Rumi Ansari 7 years, 6 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Derive an expression for conductivity in terms of mobility.

Posted by Rumi Ansari 7 years, 6 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

an el

Posted by Nishant Patel 7 years, 6 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

How to Demagnetise the magnet

Posted by Akhil Jamwal 7 years, 6 months ago

CBSE > Class 12 > Physics

3 answers

Ankita Vats 7 years, 6 months ago

By heating the magnet.

Sourin Roy 7 years, 6 months ago

it can also be done by hammering it or immersing it in a boiling solution of a very dense liquid

Kalindi Yadav 7 years, 6 months ago

Permanent magnets can be demagnetized in the following ways: Heating a magnet past its Curie point will destroy the long range ordering.

ANSWER

When is our physics exam ?? 7th or on 9th March . Asking this just for confirmation becz some websites are claiming it to be on 9th instead of 7th .

Posted by Vinayak Luha 7 years, 6 months ago

CBSE > Class 12 > Physics

4 answers

Piyush K 7 years, 6 months ago

7

Priya Prakash S 7 years, 6 months ago

7

Garima Suyal 7 years, 6 months ago

7

Vinillla Yerukola 7 years, 6 months ago

7

ANSWER

Comparing to last 5 years boards paper, sample paper for 2018 are quite difficult(higher difficulty level). Will the boards paper also be of this difficulty level like these sample paper??

Posted by Divyansh Rohatgi 7 years, 6 months ago

CBSE > Class 12 > Physics

3 answers

Priya Prakash S 7 years, 6 months ago

Only direct questions this year

Priya Prakash S 7 years, 6 months ago

No

Vinillla Yerukola 7 years, 6 months ago

Then diffidently we will die

ANSWER

Why the light coming from space is unpolarised

Posted by Aditi Roy 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Kalindi Yadav 7 years, 6 months ago

A kind of light in which the electric field vector takes all possible directions in the transverse plane rapidly and randomly during the time of measurement is called unpolarized light. Since the the light of the space takes all possible directions, it is said to be unpolarized light. When the unpolarized light falls on the transparent surface at an angle of incidence equal to the polarizing angle or Brewster's angle, then it is completely plane polarized.

ANSWER

Equipotential surface of 2 +ve charges

Posted by Harsh Pandey 7 years, 6 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Transistor as a switch bhi Nahi hai portion me I think?

Posted by Pranjali Mahajan 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Sunaina Malik 7 years, 6 months ago

Yes u r right ....nhi h wo

ANSWER

A 500 microC charge is at the center of the square of side 10 cm. Find the work done in moving a charge of 10 micro C between two diagonally opposite points on the square

Posted by Navneet Bajpai 7 years, 6 months ago

CBSE > Class 12 > Physics

2 answers

Kalindi Yadav 7 years, 6 months ago

Electric potential by charge 500 μC at the diagonally opposite points on the square is same. So the potential difference is zero between the diagonally opposite points on the square. Work done = Potential difference x charge = zero

Prerna Pahwa 7 years, 6 months ago

Zero

ANSWER

A coil wire of certain radius has 600 turns and inductance 108mH .What will be the inductance of the other similar coil with 500 turns.

Posted by Anay Patidar 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Kalindi Yadav 7 years, 6 months ago

L1=108 mH, N1=600 ,N2=500 L1/L2=N1/N2²=108×(500)²/(600)² L2=108×25/36=75 mH

ANSWER

Lens makers formula?

Posted by Gopika Malu 7 years, 6 months ago

CBSE > Class 12 > Physics

1 answers

Birendra Pattnaik 7 years, 6 months ago

1/f={μ˙-μ°/μ°}{1/R˙-1/R°}

ANSWER

Why photodiodes are reverse biased?

Posted by Ayush Jain 7 years, 6 months ago

CBSE > Class 12 > Physics

2 answers

Ankita Vats 7 years, 6 months ago

If we make it forward biased than it not works it works only on reverse biasing. In forward biased there will be no flow of current.

Pranjali Mahajan 7 years, 6 months ago

Because its easier to detect e in reverse biased

ANSWER

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