Tags Class 12th

Class 12th

Get insights from 12k questions on Class 12th, answered by students, alumni, and experts. You may also ask and answer any question you like about Class 12th

Follow Ask Question

12k

Questions

Discussions

Active Users

Followers

New answer posted

a year ago

Class 12th Physics Ray Optics and Optical Instruments

A light ray enters through a right angled prism at point $P$ with the angle of incidence $3 0^{?}$ as shown in figure. It travels through the prism parallel to its base $B C$ and emerges along the face $A C$ . The refractive index of the prism is:

0 Follower 155 Views

alok kumar singh

Contributor-Level 10

$A = 9 0^{?}$

In prism, $r_{1} + c = A$

$r_{1} = 9 0^{?} - c$ …(i)

$sin c = \frac{1}{μ} \Rightarrow cos c = \frac{\sqrt[]{μ^{2} - 1}}{μ}$

$\Rightarrow$ Apply Snell's law, on incidence surface

$1 \cdot sin 3 0^{?} = μ sin (r_{1}) \Rightarrow 1 * \frac{1}{2} = μ * sin (9 0^{?} - c)$

$\frac{1}{2} = μ * \frac{\sqrt[]{μ^{2} - 1}}{μ}$

On squaring $\frac{1}{4} = μ^{2} - 1$

$\Rightarrow μ^{2} = \frac{5}{4} \Rightarrow μ = \frac{\sqrt[]{5}}{2}$

0 0

New answer posted

a year ago

Class 12th Nuclei

The minimum energy required to launch a satellite of mass $m$ from the surface of earth of mass $M$ and radius $R$ in a circular orbit at an altitude of $2 R$ from the surface of the earth is:

0 Follower 4 Views

alok kumar singh

Contributor-Level 10

Apply energy conservation,

$U_{i} + K_{i} = U_{f} + K_{f}$

$\Rightarrow - \frac{G M m}{R} + K_{i} = - \frac{G M m}{3 R} + \frac{1}{2} m v^{2}$

$\Rightarrow - \frac{G M m}{R} + K_{i} = - \frac{G M m}{3 R} + \frac{1}{2} * m * \frac{G M}{3 R}$

$\Rightarrow K_{i} = - \frac{1}{6} \frac{G M m}{R} + \frac{G M m}{R}$

$K_{i} = \frac{5}{6} \frac{G M m}{R}$

0 0

New answer posted

a year ago

Class 12th Atoms

The following graph represents the $T - V$ curves of an ideal gas (where $T$ is the temperature and $V$ the volume) at three pressures $P_{1}, P_{2}$ and $P_{3}$ compared with those of Charles's law represented as dotted lines.

0 Follower 9 Views

alok kumar singh

Contributor-Level 10

At same temperature, curve with higher volume corresponds to lower pressure.

$V_{3} > V_{2} > V_{1}$

$\Rightarrow P_{1} > P_{2} > P_{3}$

(We draw a straight line parallel to volume axis to get this)

0 0

New answer posted

a year ago

Class 12th Physics

If the mass of the bob in a simple pendulum is increased to thrice its original mass and its length is made half its original length, then the new time period of oscillation is $\frac{x}{2}$ times its original time period. Then the value of $x$ is:

0 Follower 14 Views

alok kumar singh

Contributor-Level 10

$T^{'} = 2 π \sqrt[]{\frac{?^{'}}{g}}$ where $t^{'} = \frac{l}{2}$

$T = 2 π \sqrt[]{\frac{t}{g}}$

$T^{'} = \frac{x}{2} T$

$2 π \sqrt[]{\frac{t}{2 g}} = \frac{x}{2} 2 π \sqrt[]{\frac{t}{g}}$

$\frac{1}{\sqrt[]{2}} = \frac{x}{2} \Rightarrow x = \sqrt[]{2}$

0 0

New answer posted

a year ago

Class 12th Chemistry

The highest number of helium atoms is in

0 Follower 7 Views

Payal Gupta

Contributor-Level 10

(1) 4 mol of $= 4_{A}$ atoms

(2) 4 u of $= \frac{4 u}{4 u} = 1$ atom

(3) 4 g of Helium $= \frac{4}{4}$ mole $= 1$ mole $= N_{A}$ He atom

(4) $2.2710982$ of He at STP $= \frac{2.271}{22.710982}$ mole

$= 0.1$

$= 0.1_{A}$

0 0

New answer posted

a year ago

Class 12th Physics

A tightly wound 100 turns coil of radius 10 cm carries a current of 7 A . The magnitude of the magnetic field at the centre of the coil is (Take permeability of free space as $4 π * 1 0^{- 7} SI$ units):

0 Follower 10 Views

alok kumar singh

Contributor-Level 10

The magnitude of magnetic field due to circular coil of $N$ turns is given by

$B_{C} = \frac{μ_{0} i N}{2 R}$

$= \frac{4 π * 1 0^{- 7} * 7 * 100}{2 * 0.1}$

$= 4.4 * 1 0^{- 3} T$

$= 4.4 mT$

0 0

New answer posted

a year ago

Class 12th Physics

A thin spherical shell is charged by some source. The potential difference between the two points $C$ and $P$ (in V) shown in the figure is:

(Take $\frac{1}{4 π ε_{0}} = 9 * 1 0^{9}$ SI units)

0 Follower 24 Views

alok kumar singh

Contributor-Level 10

For uniformly charged spherical shell,

$V = \frac{k q}{R} (For r \leq R)$

$∴ V_{C} = V_{P}$

$V_{C} - V_{P} = Zero$

0 0

New answer posted

a year ago

Class 12th Dual Nature of Radiation and Matter

The maximum elongation of a steel wire of 1 m length if the elastic limit of steel and its Young's modulus, respectively, are $8 * 1 0^{8} N m^{- 2}$ and $2 * 1 0^{11} N m^{- 2}$ , is:

0 Follower 9 Views

alok kumar singh

Contributor-Level 10

In the case for maximum elongation,

Stress = Elastic limit

$δ_{m a x} = \frac{σ_{elastic} * L}{Young's modulus} = \frac{8 * 1 0^{8} * 1}{2 * 1 0^{11}} = 4 * 1 0^{- 3}$

$= 4 mm$

i.e. maximum elongation is 4 mm

0 0

New answer posted

a year ago

Class 12th Physics

In an ideal transformer, the turns ratio is $\frac{N_{P}}{N_{S}} = \frac{1}{2}$ . The ratio $V_{S} : V_{P}$ is equal to (the symbols carry their usual meaning) :

0 Follower 8 Views

alok kumar singh

Contributor-Level 10

According to transformer ratio,

$\frac{V_{S}}{V_{P}} = \frac{N_{S}}{N_{P}} = 2 : 1$

0 0

New answer posted

a year ago

Class 12th Physics Wave Optics

A thin flat circular disc of radius 4.5 cm is placed gently over the surface of water. If surface tension of water is $0.07 N m^{- 1}$ , then the excess force required to take it away from the surface is

0 Follower 11 Views

alok kumar singh

Contributor-Level 10

Excess force $= T * 2 π R$

$= \frac{7}{100} * 2 * 3.14 * \frac{4.5}{100}$

$= 197.82 * 1 0^{- 4}$

$= 19.8 * 1 0^{- 3} N$

$= 19.8 mN$

0 0

Get authentic answers from experts, students and alumni that you won't find anywhere else

On Shiksha, get access to

67k Colleges
1.2k Exams
717k Reviews
1850k Answers

Community GuidelinesUser Points System

QuestionsDiscussionsTags

Need guidance on career and education? Ask our experts

Your Question

Class 12th

Questions

Discussions

Active Users

Followers

All

Discussions

Unanswered Questions

Share Your College Life Experience