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

Focal lenth of a convex lens is given by (t-1) 1/r1 - 1/r2.... where t is refractive index Its given that f = r1 = r2= r 1/r =( t-1) 1/r -1/r By solving it .... we will get that t= 1.5

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A small ink dot on a paper is seen through a glass slab of thickness 4cm and refractive index 1.5 .. The dot appears to be raised by how much cm???

Posted by Mohit Sepat 7 years, 3 months ago

CBSE > Class 12 > Physics

0 answers

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What is the refractive index of a medium in which light travels with a speed of 2×10 raise to power 8 m/s ???? And how??? Pls give answer as soon as.

Posted by Mohit Sepat 7 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Rahul Singh 7 years, 3 months ago

1.5

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Half life of a radioactive substance is 20 days . What percentage of a sample will decay in 10 days 25%,less than 25% or more than 25%

Posted by Abc Kamboz 7 years, 3 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Why ambulance signal is blue instead of red

Posted by Anuksha V 7 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Tushar Jaryal 7 years, 3 months ago

as it is found that at night our mind will perceive that a lamp emitting a heigher frequency and shorter wavelength(eg blue or violet) of light will appear to be moving closer(if car is 10 m away from us it will look 6m away) while light with lower frequency and shorter wavelenght (red) appear to move away..i hope u will understand it..

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Which is dangerous AC or DC?

Posted by Parakram Singh Chauhan 7 years, 3 months ago

CBSE > Class 12 > Physics

2 answers

Satyam Kumar 7 years, 3 months ago

In term of voltage AC is dangerous. In term of current DC is dangerous.

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G K 7 years, 3 months ago

220V AC > 220V DC becoz peak value of AC is 311V

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Find the change in current in an inductor of 10H in which the emf induced is 300V in 1/100 seconds also find the change in magnetic flux ?

Posted by Dharminder Singh 7 years, 3 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

What is threshold frequency ? What is cutoff potential? What photoelectric emissions? V

Posted by Aman Sikarwar 7 years, 3 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

What is wattless current & choke coil and what is its principle

Posted by Aman Sikarwar 7 years, 3 months ago

CBSE > Class 12 > Physics

2 answers

Satyam Kumar 7 years, 3 months ago

In an AC circuit the avg.power is zero is called wattless current. Chock coil is electrical instrument which is used to control AC which is based on the principal of self induction.

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Manish Yadav 7 years, 3 months ago

When average power is zero then the term wattless current is - I(rms)sin¤ Choke coil is simply a inductive circuit as avg. Power is zero in this case

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What if i told u that IAM BATMAN

Posted by Arslaan Panwar 7 years, 3 months ago

CBSE > Class 12 > Physics

6 answers

Arslaan Panwar 7 years, 2 months ago

Swati jha thats nice

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Hy Shona 7 years, 2 months ago

I am princess

1Thank You

Arslaan Panwar 7 years, 3 months ago

Are swati jha yrr.. tumhe kab samajh aayega ke me majak kar raha hoen bas

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Hy Shona 7 years, 3 months ago

I will say surely u are trying to fool us

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Arslaan Panwar 7 years, 3 months ago

???

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G K 7 years, 3 months ago

U r fool....

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If the refracting telescope is used to view the moon , what is the diametre of the moon formed by the objective lens ? The diametre of the moon is 3480000m and the lunar orbit is 380000000m , the focal length of the objective is 15cm and for eye piece 1cm .

Posted by Yagyesh Dubey 7 years, 3 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Wattless current

Posted by Aman Maurya 7 years, 3 months ago

CBSE > Class 12 > Physics

2 answers

Manish Yadav 7 years, 3 months ago

I (rms)sin¤

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Deepak Jindal 7 years, 3 months ago

In an ac circuit when there is no consumed power is called wattless current.

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What are the imp. Topics in ray optics

Posted by Mohit Sepat 7 years, 3 months ago

CBSE > Class 12 > Physics

2 answers

Mohit Sepat 7 years, 3 months ago

Thanks

1Thank You

Manish Yadav 7 years, 3 months ago

Compound microscope , astronomical telescope ,lens and mirror maker formula

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What is momemtum

Posted by Rudra Gupta 7 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Rudra Gupta 7 years, 3 months ago

The product of mass and velocity of any object is called momemtum

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Why a perpendicular magnetic force cannot change the magnitude of velocity

Posted by Abd Fan 7 years, 3 months ago

CBSE > Class 12 > Physics

3 answers

Deepak Jindal 7 years, 3 months ago

W=0

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Manish Yadav 7 years, 3 months ago

As F = macos¤ and here both are perpendicular to each other so ¤ = 90 and cos¤ is = 0 so force is zero ans also w = F. S so w=0 as F = 0

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Ashish Shrivas 7 years, 3 months ago

Work=0

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What is law of malus

Posted by Akash Rounit 7 years, 3 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Explain the principle of moving coil galvanometer?

Posted by Rahul Singh 7 years, 3 months ago

CBSE > Class 12 > Physics

3 answers

Satyam Kumar 7 years, 2 months ago

The moving coil of galvanometer is based on the principal of magnetic torque in current carrying loop. Tuo=NiAB........(i) Restoring torque= Kfi......(ii) Net balancing torque acting on it Therefore,. NiAB=kfi i=kfi/NAB.

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Niku Garg 7 years, 3 months ago

Jo current hoaga coil mein jo magnetic field mein hoagi usme ek torque lagega vo hota h mcg ka principal

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Anamika Shukla 5 years, 8 months ago

Why

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Sketch the electric field lines for uniform

Posted by Aaditya Sharma 7 years, 3 months ago

CBSE > Class 12 > Physics

1 answers

Anamika Shukla 7 years, 3 months ago

Why

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Why the core of sun is not more hotter as compare to the surround?

Posted by Sahil Patre 7 years, 3 months ago

CBSE > Class 12 > Physics

0 answers

ANSWER

Y phy is very much tough:-) ??

Posted by Swetha Sri 7 years, 3 months ago

CBSE > Class 12 > Physics

3 answers

Deepak Jindal 7 years, 2 months ago

Physics is interesting subject bcoz of numericals........ Physics is easy??????? But it depends on you..

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Hy Shona 7 years, 3 months ago

It more interesting

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Raunak _ Pandey ?? 7 years, 3 months ago

No , it is very easy , nothing is tough or easy it just matters about our interest

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Why the electric field lines never cross each other

Posted by Somdatt Kakoria 7 years, 3 months ago

CBSE > Class 12 > Physics

4 answers

Hy Shona 7 years, 3 months ago

If they cross each other then it show two direction which is not possible

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Anamika Shukla 7 years, 3 months ago

I dont know

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Sahil Patre 7 years, 3 months ago

At each point, the direction (tangent) of the field line is in the direction of the electric field. At each point in space (in the absence of any charge), the electric field has a single direction, whereas crossing field lines would somehow indicate the electric field pointing in two directions at once in the same location. Field lines do cross, or at least intersect, in the sense that they converge on charge. If there is a location with charge, the field lines will converge on that point. However we typically say the field lines terminate on the charge rather than crossing there.

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Sahil Patre 7 years, 3 months ago

Let if they cross each other we obtain two direction of electric field at a point which is not possible.

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The figure given ,mark the polarity of A andB of acapacitor when the magnet are quickly moved toward the coil

Posted by Vinayak Mishra 7 years, 3 months ago

CBSE > Class 12 > Physics