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Class 12th Physics

A 8 V Zener diode along with a series resistance R is connected across a 20V supply (as shown in the figure). If the maximum Zener current is 25 mA, then the minimum value of R will be_______ $Ω$ .

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alok kumar singh

Contributor-Level 10

$i_{(z e n e r - m a x)} = 25 m A$

20 – i_maxR – 8 = 0

i_max R = 12At minimum zener current $(μ A) : -$

20 - i_{m i n} R - i_{m i n} R_{L} = 0

$\frac{R}{R_{L}} = \frac{12}{8} = \frac{3}{2}$

$l_{m i n} R = 12$

$i_{m i n} R_{L} = 8$

At max^m zener current –

$20 - i_{m a x} R - 8 = 0$

$i_{L} = O {a s i_{z} m a x^{m} = 25 m A}$

i_maxR = 12v

25 * 10^-3 R = 12

$R = \frac{12 * 1 0^{3}}{25} = 12 * 40 = 480 Ω$

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New answer posted

a year ago

Class 12th Physics Electrostatic Potential and Capacitance

A parallel plate capacitor with width 4cm, length 8cm and separation between the plates of 4mm is connected to a battery of 20V. A dielectric slab of dielectric constant 5 having length 1cm, width 4cm and thickness 4mm is inserted between the plates of parallel plate capacitor. The electrostatic energy of this system will be ___________ $\in_{0} J .$

(Where $\in_{0}$ is the permittivity of free space)

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Vishal Baghel

Contributor-Level 10

$C_{e f f} = [\frac{ε_{0} (7 * 4)}{4 / 10} + \frac{5 ε_{0} (1 * 4)}{4 / 10}] * 1 0^{- 2}$

$C_{e f f} = 1.2 ε_{0}$

Energy = $\frac{1}{2} C_{e f f} V^{2}$ $\frac{}{}_{}^{}$

$\frac{1}{2} (1.2 ε_{0}) (20) (20) = 240 ε_{0}$

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New answer posted

a year ago

Class 12th Physics

A modulating signal 2sin (6.28 * 10⁶)t is added to the carrier signal 4 sin(12.56 *10⁹)t for amplitude modulation. The combined signal is passed through a non-linear square law device. The output is then passes through a band pass filter. The bandwidth of the output signal of band pass filter will be_________ MHz.

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alok kumar singh

Contributor-Level 10

Modulating signal 2sin (6.28 * 10⁶)t

Carrier signal 4 sin (12.56 * 10⁹)t

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New answer posted

a year ago

Class 12th Physics

As shown in the figure, in steady state, the charge stored in the capacitor is ____________* 10^-⁶C.

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Vishal Baghel

Contributor-Level 10

$q = C V_{100 Ω}$

$= (1.1 * 1 0^{- 6}) (\frac{10}{R + r} R)$

$= 1.1 * 1 0^{- 6} (\frac{10}{110} * 100)$

$= 10 μ C$

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New answer posted

a year ago

Class 12th Physics

A conducting circular loop is placed in X – Y plane in presence of magnetic field $\vec{B} = (3 t^{3} \hat{j} + 3 t^{2} \hat{k})$ in SI unit. If the radius of the loop is 1m. The induced emf in the loop, at time, t = 2s is npV. The value of n is__________.

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Vishal Baghel

Contributor-Level 10

$? = \vec{B} . \vec{A}$

$= (3 t^{3} \hat{j} + 3 t^{2} \hat{k}) . (π {(1)}^{2} \hat{k})$

$? = 3 t^{2} π$

$E_{i n d} = | \frac{d ?}{d t} | = 6 t π$

at t = 2, E_ind = 12

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a year ago

Class 12th Physics

A thin prism of angle 6° and refractive index for yellow light (n_Y) 1.5 is combined with another prism of angle 5° and n_Y = 1.55. The combination produces no dispersion. The net average deviation $(δ)$ produced by the combination is ${(\frac{1}{x})}^{o}$ . The value of x is____________.

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Vishal Baghel

Contributor-Level 10

$δ = A (μ_{y} - 1) - A^{1} (μ_{y}^{1} - 1)$

$= 6 (1.5 - 1) - 5 (1.55 - 1)$

$= \frac{1}{4}$

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New answer posted

a year ago

Class 12th Physics

In the given figure of meter bridge experiment, the balancing length AC corresponding to null deflection of the galvanometer is 40 cm. The balancing length, if the radius of the wire AB is doubled, will be__________cm.

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Vishal Baghel

Contributor-Level 10

Independent of are a is case of uniform wire

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a year ago

Class 12th Physics Wave Optics

Nearly 10% of the power of a 110 W light bulb is converted to visible radiation. The change in average intensities of visible radiation, at a distance of 1 m from the bulb to a distance of 5 m is a * 10^‑2 W/m². The value of 'a' will be________.

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alok kumar singh

Contributor-Level 10

P = 10% of 110W = 11W

(Visible)

$I_{1} - I_{2} = \frac{ρ}{4 π} (\frac{1}{r_{1}^{2}} - \frac{1}{r_{2}^{2}})$

$= \frac{11}{4 * \frac{22}{7}} (\frac{1}{1} - \frac{1}{25})$

$\frac{7}{8} * (\frac{24}{25}) = a * 1 0^{- 2} W / m^{2}$

$\frac{28 * 24}{8} * 1 0^{- 2} = a * 1 0^{- 2}$

=84 * 10^-2 = a * 10^-2 = a = 84

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New answer posted

a year ago

Class 12th Maths

Let S $= {z \in C : z^{2} + \bar{Z} = 0} .$ Then $\sum_{z \in R}^{} (R e (z) + I m (z))$ is equal to

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Payal Gupta

Contributor-Level 10

take z = x + iy

$z^{2} + \bar{z} = 0$

$\Rightarrow x^{2} - y^{2} + x + i 2 x y - y i = 0$

$\Rightarrow x^{2} - y^{2} + x = 0 a n d y (2 x - 1) = 0$

if y = 0 x = 0, 1

$i f x = \frac{1}{2} \Rightarrow y = \pm \frac{\sqrt[]{3}}{2}$

$Σ (R e (z) + l m (z)) = (0 - 1 + \frac{1}{2} + \frac{1}{2}) + (0 + 0 + \frac{\sqrt[]{3}}{2} - \frac{\sqrt[]{3}}{2}) = 0$

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New answer posted

a year ago

Class 12th Maths Matrices

Let S be the set containing all 3 * 3 matrices with entries from ${- 1, 0, 1}$ . The total number of matrices $A \in S$ such that the sum of all the diagonal elements of A^TA is 6 is

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Payal Gupta

Contributor-Level 10

Let A = $[\begin{matrix} a & b & c \\ d & e & f \\ 9 & h & i \end{matrix}]$

Now A^TA

trace will be $a^{2} + b^{2} + c^{2} + d^{2} + e^{2} + f^{2} + 9^{2} + h^{2} = 6$

total ways = ⁹C₆.2⁶.1.1.1 = 5376

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