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For converting a galvanometer into an ammeter, a shunt resistance of small value is used in parallel whereas in the case of a voltmeter a resistance of large value is used in series . Explain , why ?

Posted by Dinesh Kumar Sahu 7 years ago

CBSE > Class 12 > Physics

1 answers

Aayushi Srivastava 7 years ago

since galvanometer is very sensitive as it produce large deflection when small current passed through it. so to measure large current with it ,a shunt resistance is used,so that only desired current will pass through galvanometer and remaining current will pass through shunt . In case of voltmeter , large resistance is connected in series so that it can prevent the decrease in potential difderence across it.

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A coke coil in series with a lamp is connected to a dc line. The lamp is seen to shine brightly. Insertion of an iron core in the choke causes no change in the lamps brightness. Predict the corresponding observation if the connection is to an ac line.

Posted by Aman Jakhar 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

How is zener diode fabricated so as to make it special purpose diode

Posted by Dipankar Kundu 7 years ago

CBSE > Class 12 > Physics

1 answers

Prabhat Singh 7 years ago

In series combination and reverse biased

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ANSWER

Plzz..answer A 20 micro columb charge is placed in a uniform nagnetic field of 2T. How much force does the charge experience????

Posted by Suhani Rana? 7 years ago

CBSE > Class 12 > Physics

2 answers

Prabhat Singh 7 years ago

Yes it is zero

3Thank You

. . 7 years ago

Is it zero ? cause if it is not moving the magnetic force is zero

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ANSWER

When a photo sensitive material is irradiated

Posted by Anna Jiji 7 years ago

CBSE > Class 12 > Physics

1 answers

. . 7 years ago

Electrons are emitted if energy is greater or equal to threshold energy

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Since the current in the forward bias is known to be more than the current in the reverse bias. So what is the reason then to operate the photo diode in reverse bias

Posted by Chetan Keshri 7 years ago

CBSE > Class 12 > Physics

2 answers

Kriti Jaiswal 7 years ago

Becoz fractional change in majority charge carrier is less than minority charge carrier

1Thank You

Priyanshu Bisht 7 years ago

Due to minority charge carrier

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What happen when inteferance ocuurs in diffrent medium?

Posted by Pagaal Sciencetist 7 years ago

CBSE > Class 12 > Physics

1 answers

Aman Jakhar 7 years ago

The interference of waves causes the medium to take on a shape that results from the net effect of the two individual waves upon the particles of the medium.

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What is tunnelling effect?

Posted by Nikku Prajapat 7 years ago

CBSE > Class 12 > Physics

1 answers

Aman Jakhar 7 years ago

tunnelling is the mechanical phenomenon where a subatomic particle passes through a potential barrier that it cannot surmount under the provision of classical mechanics.

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Diffraction throug one slit ????

Posted by Ayush Srivastava 7 years ago

CBSE > Class 12 > Physics

1 answers

Dipankar Kundu 7 years ago

What do you want to know about that topic

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How displacement current form?

Posted by Rohit Pandit 7 years ago

CBSE > Class 12 > Physics

3 answers

Anjali Kalange 7 years ago

Displacement current comes into play when EF and hence the flux changes wrt time.

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Aman Jakhar 7 years ago

displacement current density is the quantity ∂D/∂t appearing in Maxwell's equations that is defined in terms of the rate of change of D, the electric displacement field

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Rishabh Pandey 7 years ago

When electric field is developed b|w 2 parallel plate capacitor

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A metallic rod of 1m length is rotated with afrequency of 50 rev/s,with one end hinged at the center and the other end at the circumference of a circular metallic ring of radius 1m about an axis passing thriugh the center and perpendicular to the plane of the ring.A constant and uniform magnetic field of IT and parallel to the axis is present everywhere.what is the emf betwwen the center and the matallic ring?

Posted by Sattu Maravi 7 years ago

CBSE > Class 12 > Physics

1 answers

Soomo Banerjee 7 years ago

1/2Bwr*2

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What do you mean by internet ?write any four application of internet

Posted by Sattu Maravi 7 years ago

CBSE > Class 12 > Physics

1 answers

Pagaal Sciencetist 7 years ago

applications of internet . 1.used in downloading vedio, audio and data. 2.it is easiest way to connected throught the world by means of facebook, twitted google etc. 3.it helps in receiving mail and email. 4.to manipulate the various computer system .

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Name the electromagnetic radiation s used for (a) water purification, and (b) eye surgery

Posted by Anushka Parchake 7 years ago

CBSE > Class 12 > Physics

3 answers

Aman Jakhar 7 years ago

UV radiation

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Suhani Rana? 7 years ago

UV radiation are used for both i.e for water purification and for eye surgery.

2Thank You

Shivam Bhati 7 years ago

UV for water purification. LASER for eye surgery

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What is the significance of minimum deviation in prism

Posted by Shekhar Kr 7 years ago

CBSE > Class 12 > Physics

1 answers

Aman Jakhar 7 years ago

Light is deflected as it enters a material with refractive index > 1. A ray of light is deflected twice in a prism. The sum of these deflections is the deviation angle. When the entrance and exit angles are equal, the deviation angle of a ray passing through a prism will be minimal.

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What is the significance of m deviation in prism

Posted by Shekhar Kr 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Which charge is found on earth

Posted by Jairam Yadav 7 years ago

CBSE > Class 12 > Physics

1 answers

Jairam Yadav 7 years ago

Neutral

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What are the most important topics in physics this year.

Posted by Mihir Gupta 7 years ago

CBSE > Class 12 > Physics

2 answers

Aman Jakhar 7 years ago

NCERT with previous years board paper

2Thank You

Priya Kashyap 7 years ago

NCERT is more than enough for cbse board exam.

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ANSWER

Kabhi bhi phy ke paper mein discoveres(scientists) ke names puche gye hain.......ya koi possibility hai ki puche ja sakte hain..........plz ans this questionnn

Posted by Isha Ahuja 7 years ago

CBSE > Class 12 > Physics

3 answers

Aniket Jaiswal 7 years ago

Can't possible

1Thank You

Aman Jakhar 7 years ago

Never

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Priya Kashyap 7 years ago

Not necessary

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Explanation of binding energy per nucleon as a function of mass number ?

Posted by Anjali Sheokand 7 years ago

CBSE > Class 12 > Physics

0 answers

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Explain the need for modulation for long distance transmission

Posted by Jaya Prithiksha 7 years ago

CBSE > Class 12 > Physics

3 answers

Mihir Gupta 7 years ago

Modulation is done for increasing the frequency of signals. As low frequency signal cancer cannot be transmitted far.

1Thank You

Nitika Neb 7 years ago

It is due to the following reasons that the length of antenna is not much mixing of signal happens an effective power radiated by antenna

1Thank You

Shivam Chugh 7 years ago

Modulation is necessary to transmit low frequency singnal, as it increases the frequency of the signal. So, our message gets transmitted to where we want

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What is the electric flux througj a cube of side 1 cm in a medium of refractive index 1.65. What is the nature of the lens?

Posted by Aadi Lahare 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Cause of quantization of charge

Posted by Prachi Saini 7 years ago

CBSE > Class 12 > Physics

1 answers

Sarthak Bhai 7 years ago

Transfer of intergral number of electoons

4Thank You

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Howis the working of telescope diff from that of a micro scope

Posted by Mihir Setia 7 years ago

CBSE > Class 12 > Physics

1 answers

Sarthak Bhai 7 years ago

The orientation of.eye piece and objective are differ in both in telescope objective is of large aperture while in microscope it diamter is small

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two baal drawn in two different liquid one of them appear large and other small in their respective size

Posted by Sumit Lathuriya 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Working of AC generatior explain

Posted by Chanchal Sharma 7 years ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Write Three important factor which justify the need of modulating a message signal. Show diagrammatically how an amplitude modulated signal is superimposed on carrier wave?

Posted by Priya Ahirwar 7 years ago

CBSE > Class 12 > Physics

1 answers

Gaurav Seth 7 years ago

Three factors for the need of modulating a message signal:

a) Size of the antenna or aerial should be /4.

b) Effective power radiated by an antenna should be close to
c) Interference of signals from different transmitters. In order to avoid the interference of the signals, high frequency is required which can be acquired by modulation.

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Diagram and working of cyclotron?

Posted by Kanishka Singh 7 years ago

CBSE > Class 12 > Physics

1 answers

Gaurav Seth 7 years ago

Principle of cyclotron :
The working of the cyclotron is that a positively charged particle can be accelerated to sufficiently high energy using smaller oscillating electric field by making the cyclotron cross the same elctric field time and again by magnetic field.

Working of cyclotron:
1.The positive ion which is to be accelerated is bought at a point in between D₁ and D_2.Suppose, D₁is at a negative potential and D₂ is at a positive potential. Hence, the ion will be accelerated towards D₁.
2. The ion will be in a free space once it enters D₁ and therefore, it moves with a constant speed say, v.
3. A perpendicular magnetic field B is applied. So, the ion will undergo a circular path of radius r in D₁ .
The circular path is given by,

where, m is the mass of ion and,
q is the charge on ion.


4. Now, time taken by an ion to describe a semicircular path is given by,

t =

5. If, this time during which the positive ion describes a semi-circular path is the time during which half-cycle of electric oscillator is completed, then as the ion arrives in the gap between the two dees, polarity of the two dees gets reversed. Consequently, positive ion is accelerated towards D₂ and the ion enters D₂ with greater speed which will remain constant in D₂.
6. Ion will describe a semicircular path of greater radius due to perpendicular magnetic field and will again arrive in a gap between the two dees exactly at that instant when, the polarity of two dees is reversed.
7. Thus, positive ion will keep on accelerating everytime it comes into the gap between the dees and will describe a circular path of greater and greater radius henceforth, acquiring sufficiently high kinetic energy.