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8 months ago

Class 12th Physics Wave Optics

White light is passed through a double slit and interference is observed on a screen 1.5m away. The separation between the slits is 0.3mm. The first violet and red fringes are formed 2.0mm and 3.5mm away from the central white fringes. The difference in wavelengths of red and violet light is………nm.

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Vishal Baghel

Contributor-Level 10

For first fringe

$\frac{d y_{1}}{D} = 1 * λ_{1} [n = 1] λ_{1} \to$ Red wavelength

$\frac{d y_{2}}{D} = 1 * λ_{2} [n = 1] λ_{2} \to$ violet wavelength

$\frac{d}{D} (y_{1} - y_{2}) = λ_{1} - λ_{2}$

$y_{1} - y_{2} = \frac{D}{d} (λ_{1} - λ_{2})$

= $\frac{0.3 * 1 0^{- 3}}{1.5} (3.5 - 2) * 1 0^{- 3}$

= 300 * 10^-9

= 300 nm

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New answer posted

8 months ago

Class 12th Physics Moving Charges and Magnetism

If the maximum value of accelerating potential provided by a ratio frequency oscillator is 12 kV. The number of revolution made by proton in a cyclotron to achieve one sixth of the speed of light is_________.

$[m_{p} = 1.67 * 1 0^{- 27} k g, e = 1.6 * 1 0^{- 19} C, S p e e d o f l i g h t = 3 * 1 0^{8} m ? / ? s]$

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alok kumar singh

Contributor-Level 10

2nqV = $\frac{1}{2} m v^{2}$

$n = \frac{m v^{2}}{4 q V}$

$= \frac{1.67 * 1 0^{- 27} * {(0.5 * 1 0^{8})}^{2}}{4 * 1.6 * 1 0^{- 19} * 12 * 1 0^{3}} = 543$

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8 months ago

Class 12th Physics Magnetism and Matter

Two short magnetic dipoles m1 and m2 each having magnetic moment of 1 Am² are placed at point O and P respectively. The distance between OP is 1 meter. The torque experienced by the magnetic dipole m2 due to the presence of m₁ is____________ * 10^-7 Nm.

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Vishal Baghel

Contributor-Level 10

$τ_{2} = B_{1} M_{2} S m 90 °$

= B₁ M₂

$= (\frac{μ_{0}}{4 π} * \frac{m_{1}}{r^{3}}) * m_{2}$

= $1 0^{- 7} \frac{1}{1^{3}} * 1$

= 10^-7 N – m

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New answer posted

8 months ago

Class 12th Physics Wave Optics

A source of light is placed in front of a screen. Intensity of light on the screen in I. Two Polaroids P₁ and P₂ are so placed in between the source of light and screen that the intensity of light on screen in $\frac{I}{2} .$ P₂ should be rotated by an angle of_______ (degrees) so that the intensity of light on the screen becomes

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alok kumar singh

Contributor-Level 10

$\frac{l}{2} c o s^{2} ? = \frac{3 l}{8}$

$? c o s ? = \frac{\sqrt[]{3}}{2}$

$? ? = 30 °$

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8 months ago

Class 12th Physics Wave Optics

A source and a detector move away from each other in absence of wind with a speed of 20m/s with respect to the ground. If the detector detects a frequency of 1800 Hz of the sound coming from the source, then the original frequency of source considering speed of sound in air 340 m/s will be ……Hz.

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Vishal Baghel

Contributor-Level 10

$f' = \frac{340 - 20}{340 + 20} * f_{0}$

$\Rightarrow 1800 = \frac{320}{360} * f_{0}$

f₀ = 2025 Hz

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8 months ago

Class 12th Physics

A parallel-plate capacitor with plate area A has separation d between the plates. Two dielectric slabs of dielectric constant K₁ and K₂ of same area A/2 and thickness d/2 are inserted in the space between the plates. The capacitance of the capacitor will be given by:

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alok kumar singh

Contributor-Level 10

$C_{e q} = C + \frac{C_{1} . C_{2}}{C_{1} + C_{2}}$

$= \frac{ε_{0} \frac{A}{2}}{d} + \frac{\frac{k_{1} ε_{0} \frac{A}{2}}{\frac{d}{2}} . \frac{k_{2} ε_{0} \frac{A}{2}}{\frac{d}{2}}}{\frac{k_{1} ε_{0} \frac{A}{2}}{\frac{d}{2}} + \frac{k_{2} ε_{0} \frac{A}{2}}{\frac{d}{2}}}$

= $\frac{ε_{0} A}{d} (\frac{1}{2} + \frac{k_{1} k_{2}}{k_{1} + k_{2}})$

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8 months ago

Class 12th Physics

What equal length of an iron wire and a copper-nickel alloy wire, each of 2mm diameter connected parallel to give an equivalent resistance of 3 $Ω$ ?

(Given resistivities of iron and copper-nickel alloy wire are $12 μ Ω$ cm and 51 $μ Ω$ cm respectively)

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Vishal Baghel

Contributor-Level 10

$\frac{R_{1} R_{2}}{R_{1} + R_{2}} = 3$

$\Rightarrow \frac{(ρ_{1} \frac{l}{A}) (ρ_{2} \frac{l}{A})}{(\frac{ρ_{1} l}{A}) + (\frac{ρ_{2} l}{A})} = 3$

$= \frac{3 * [\frac{π}{4} * {(2 * 1 0^{- 3})}^{2}] [12 + 51] * 1 0^{- 6} * 1 0^{- 2}}{12 * 1 0^{- 6} * 1 0^{- 2} * 51 * 1 0^{- 6} * 1 0^{- 2}}$

$= 97$

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New answer posted

8 months ago

Class 12th Physics

A transmitting antenna at top of a tower has a height of 50m and the height of receiving antenna is 80m. What is the range of communication for Line of Sight (LoS) mode? [use radius of earth = 6400km]

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