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Class 12th Physics

Calculate the value of output voltage V₀ (in V) if the Si diode and Ge diode conduct at 0.7V and 0.3V respectively as shown in figure.

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alok kumar singh

Contributor-Level 10

$I = \frac{12 - 0.3}{5 * 1 0^{3}} = 2.34 m A$

$V_{0} = I R = (2.34 * 1 1^{- 3}) (5 * 1 0^{3}) = 11.7 V$

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6 months ago

Class 12th Physics Moving Charges and Magnetism

An electron moving with a velocity of 2 m/s along +ve x-axis at a point in a magnetic field experiences a force of 2N along -ve y-axis. If the electron moves with of a velocity of 2 m/s along +ve y-axis at the same point, it experiences a force of 2N along +ve x-axis. Find force that the electron would experience if it were moving with a velocity of 2m/s along z-axis.

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Vishal Baghel

Contributor-Level 10

v? = 2î F? = -2?
v? = 2? F? = -2î
⇒ B? is along -k? Hence v? = 2k? ⇒ F? = 0

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6 months ago

Class 12th Physics Electrostatic Potential and Capacitance

A proton and an $α$ -particle both initially at rest are accelerated in a region of electric potential difference V and gravity free space. The proton is projected with gained kinetic energy against a uniform constant electric field and comes to momentary rest after travelling a distance $S_{0}$ . If the $α$ -particle is also projected with gained kinetic energy against same electric field, it will come to momentary rest after travelling through:

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Raj Pandey

Contributor-Level 9

Gain in K.E. $=$ Loss in P.E.

$_{}$ $K_{p} = e V$ for proton

$K_{α} = 2 e V$ for $α$ - particle

Again, Loss in K.E. $=$ Work against field

$K_{p} = e E \cdot S_{0}$ for proton

$\Rightarrow e V = e E S_{0}$

$∴ S_{0} = \frac{V}{E}$

$K_{α} = 2 e E . S$ for $α -$ particle

$\Rightarrow 2 e V = 2 e E S$

$∴ S = \frac{V}{E} = S_{0}$

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6 months ago

Class 12th Physics

Two infinite line charges having linear charge density λ₁ and λ₂ are placed along the x and y axis respectively. The electric field at a point (x₁, y₁) in the first quadrant is inclined at an angle of 60° with the x-axis. Then which of the following relations is correct.

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Vishal Baghel

Contributor-Level 10

tan 60° = (2kλ? /y? )/ (2kλ? /x? )

(√3λ? /x? ) = (λ? /y? ); √3λ? y? = λ? x?

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6 months ago

Class 12th Physics

Assuming the sun to be a spherical body (e = 1) of radius R at a temperature of T K, evaluate the total radiant power, incident on Earth having radius r₀, at a distance r from the Sun, where r₀ is the radius of the earth and $σ$ is Stefan's constant.

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alok kumar singh

Contributor-Level 10

\frac{e A_{s u n} σ T^{4}}{4 π r^{2}} * A_{p r o j E a r t h}

\frac{4 π R^{2}}{4 π r^{2}} σ T^{4} π r_{0}^{2}

π \frac{R^{2}}{r^{2}} r_{0}^{2} σ T^{4}

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6 months ago

Class 12th Physics Moving Charges and Magnetism

Magnetic field exists in the region between lines PQ and RS as shown in the figure. A particle having charge to mass ratio of a enters the magnetic field as shown in the figure with a speed v. Lines PQ and RS are parallel to each other. Find the value of d such that the charged particle exits the magnetic field region with velocity perpendicular to line RS.

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Vishal Baghel

Contributor-Level 10

d = Rsin 60°

⇒ d = (mv√3)/ (qB 2) = (√3v)/ (2aB)

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6 months ago

Class 12th Physics Atoms

Amount of radiation energy emitted by unit surface area per unit time by a body is defined as its emissive power. Dimension of Emissive power is:

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Raj Pandey

Contributor-Level 9

$E = \frac{Energy}{time * Area} \Rightarrow [E] = \frac{[Energy]}{[time] [Area]} = \frac{M L^{2} T^{- 2}}{L^{2} T}$

$[E] = M L^{0} T^{- 3}$

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6 months ago

Class 12th Physics

In the circuit shown swith S is connected to position 2 for a long time and then joined to position 1. The total heat produced in resistance R₁ is:

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alok kumar singh

Contributor-Level 10

$I = \frac{E}{R_{2}}$

$U_{I n d u c t o r} = H e a t l o s s i n R_{1} = \frac{1}{2} L {(\frac{E}{R_{2}})}^{2}$

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6 months ago

Class 12th Physics

At t < 0, the capacitor is charged and the switch is opened. At t = 0 the switch is closed. The shortest time T at which the charge on the capacitor will be zero is given by:

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alok kumar singh

Contributor-Level 10

The time period of LC oscillations,

$T = 2 π \sqrt[]{L C}$

The time at which charge on the capacitor will be zero is $\frac{T}{4} .$

So t $= \frac{π}{2} \sqrt[]{L C}$

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6 months ago

Class 12th Enzymes

What are the types of enzymes?

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Vikash Kumar Vishwakarma

Contributor-Level 10

There are various types of enzymes, including lyases, ligases, isomerases, hydrolases, oxidoreductases, etc. To know about the types of enzymes in detail, refer to the article.

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