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Why are real images always inverted?

Two point objects with different masses are kept at a distance $R$ apart from each other. If the gravitational force between them is $F$, then:

Question 20

Mention three advantages of a solar cell?

A $5\text{V}$ battery and a $2\text{V}$ battery are connected to the resistances as shown. The current in the $10\Omega$ resistor is :

Regions further away from the equator receive more ___ sunlight.

What potential difference should be applied across an X-ray tube to get an X-ray of wavelength not less than $0.10\text{nm}$? $(h=6.63\times {10}^{-34}\text{Js,}c=3\times {10}^8\text{m/s},e=1.6\times {10}^{-19}\text{C})$

The refractive index of the core of an optical fiber is ${\mu }_2$​ and that of the cladding is ${\mu }_1$​. The angle of incidence on the face of the core so that the light ray just grazes at the cladding as shown in the figure is :

The refractive index of glass for light going from air to glass is $\frac{3}{2}.$ Glass to air will be :

(a) $\frac{2}{3}$

(b) $\frac{4}{5}$

(c) $\frac{4}{6}$

(d) $\frac{5}{2}$

After tracing the path of a ray of light through a glass prism a student marked the angle of incidence ($\angle$i), angle of refraction ($\angle$ r) angle of emergence ($\angle$e) and the angle of deviation ($\angle$D) as shown in the diagram. The correctly marked angles are:

The radius of a circular loop is 0.5 m and the current passing through the loop is 10A. The magnitude of magnetic field at the centre of the loop is

$(Given{\mu }_0=4\pi \times {10}^{–7}Tm/A)$

A current is passed through a wire and the power dissipated is observed to be equal to $P.$ Now the wire is stretched such that the length becomes double. If the same current is passed through the wire, then the power dissipated will be equal to



$[$0.77 Mark$]$

A body is in equilibrium, then which of the following is always true?

The output of the ideal transformer with the polarities and dots shown in the figure is given by

If a star can convert all the helium nuclei completely into oxygen nuclei, then the energy released per oxygen nuclei is

$[\text{Mass of He nucleus}=4.0026\text{amu}\text{mass of oxygen nucleus}=15.9994\text{amu},1\text{amu}=\frac{931.5}{c^2}\text{MeV}]$

Two identical thin plano-convex glass lenses $($refractive index $1.5)$ each having radius of curvature of $20\text{cm}$ are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index $1.7$. The focal length of the combination is

The $I-V$ characteristics of an $\text{LED}$ is

The cell represented in the figure is

The radiation corresponding to $3\to 2$ transition of hydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of $3\times {10}^{-4}\text{T}$. If the radius of the largest circular path followed by these electrons is $10.0\text{mm}$, the work function of the metal is close to

A convex lens of focal length $10cm$ forms a virtual image at $30cm$ from the lens. Find the position of an object from the lens.

The magnetic field inside a current carrying solenoid is

The radius of the second Bohr orbit for hydrogen atom in angstrom is:

$\text{(Planck's constant,}h=6.262\times {10}^{-34}\text{Js}:$ $\text{Mass of electron}=9.1091\times {10}^{-31}\text{kg};$ $\text{Charge of electron,}e=1.60210\times {10}^{-19}\text{C};$ $\text{permittivity of vacuum,}{\epsilon }_0=8.854185\times {10}^{-12}{\text{kg}}^{-1}{\text{m}}^{-3}{\text{A}}^2)$

In lens displacement method, for the two positions of lens, lateral size of the images are $4\text{cm}$ and $9\text{cm}$ respectively. The size of the object is

The magnetic field at a point $P$ which is at the distance of $4$ $cm$ from a long current carrying wire is ${10}^{-3}T$, the magnetic field at a distance $12$ $cm$ from the current carrying wire will be