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2 months ago

Physics NEET

What is weightage of Class 11 Physics Chapter 11 Thermodynamics in NEET and JEE Main exams?

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2 months ago

Physics Class 12th

A resistor develops 300 J of thermal energy in 15s, when a current of 2 A is passed through it. If the current increases to 3 A, the energy developed in 10s is…………….J.

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Raj Pandey

Contributor-Level 9

$H = I^{2} R t = 2^{2} * R * 15$

$\Rightarrow 300 = 60 R$

$R = 5 Ω$

Now for 3A, time = 10 sec

$H' = l^{2} R t = 3^{2} * 5 * 10 = 450 J$

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2 months ago

Physics Class 11th

Two stars of masses m and 2m at a distance d rotate about their common centre of mass in free space. The

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alok kumar singh

Contributor-Level 10

$m ω^{2} . \frac{2 d}{3} = \frac{G . m . 2 m}{d^{2}} \Rightarrow ω = \sqrt[]{\frac{3 G m}{d^{3}}}$

$T = \frac{2 π}{ω} = 2 π \sqrt[]{\frac{d^{3}}{3 G m}}$

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2 months ago

Physics Physics Electrostatic Potential and Capacitance

The equivalent capacitance between points A and B in below shown figure will be…………. $μ F .$

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Raj Pandey

Contributor-Level 9

ceq = $\frac{24 * 8}{32} = 6 μ F$

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2 months ago

Physics Class 12th

If an emitter current is changed by 4mA, the collector current changes by 3.5mA. The value of b will be:

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alok kumar singh

Contributor-Level 10

$α = \frac{Δ l_{C}}{Δ l_{E}} = \frac{3.5}{4} = \frac{7}{8}$

$β = \frac{α}{1 - α} = \frac{7 / 8}{1 - 7 / 8} = 7$

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2 months ago

Physics Physics Ray Optics and Optical Instruments

The focal length f is related to the radius of curvature r of the spherical convex mirror by:

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alok kumar singh

Contributor-Level 10

Focus of a spherical convex mirror is in the same side of centre of curvature. Thus, f = + $\frac{1}{2} r .$

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2 months ago

Physics Physics Oscillations

The first overtone frequency of an open organ pipe is equal to the fundamental frequency of a closed organ pipe. If the length of the closed organ pipe is 20cm. The length of the open organ pipe is……….cm.

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Raj Pandey

Contributor-Level 9

$H = \frac{λ}{4}$

$\Rightarrow 20 = \frac{λ}{4}$

$λ = 80 c m$

Now first overtone for open organ pipe

$L_{2} = 4 \frac{λ}{4} = λ = 80 c m$

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2 months ago

Physics Class 11th

Match List I with List II.

List I &nb

...more

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alok kumar singh

Contributor-Level 10

In isothermal process, temperature is constant.

In isochoric process, volume is constant.

In adiabatic process, there is no exchange of heat.

In isobaric process, pressure is constant.

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2 months ago

Physics Physics Thermodynamics

A steam engine intakes 50g of steam at $100 ° C$ per minute and cools it down to $20 ° C .$ If latent heat of vaporization of steam is 540 cal g1, then the heat rejected by the steam engine per minute is………….* 103 cal.