List of top Physics Questions asked in UP Board XII

An electron enters the region of \( 0.3 \, \text{T} \) magnetic field at an angle of 60° with the speed of \( 4 \times 10^5 \, \text{ms}^{-1} \). Find the radius of the helical path and the pitch (distance between two consecutive spirals) of the electron beam.
The work function of a photoelectric material is 4.0 eV. Find the wavelength of light for which the stopping potential is 5 volt.
Derive the formula for the intensity of magnetic field produced at the centre of a current carrying circular loop.
A right-angled triangle ABC, made from a metallic wire, moves at a uniform speed of 0 m/s in its plane as shown in the figure. A uniform magnetic field \( B = 0.5 \, \text{T} \) exists in the perpendicular direction to the plane. Find the induced emf in the segments BC, AC, and AB.
A point object is placed at a distance of 15 cm from a convex lens. The image is formed on the other side of the lens at a distance of 30 cm from the lens. When a concave lens is placed in contact with the convex lens, the image shifts away further by 30 cm. Calculate the focal lengths of the two lenses.
Draw a ray diagram for a reflecting telescope. Explain its working and compare it with a refracting telescope.
Find the current through the 10Ω resistor shown in the figure.
A light ray going through a prism with the angle of prism 60°, is found to have minimum deviation of 30°. What is the refractive index of the prism material?
Write an expression of refractive index of a liquid relative to air in terms of velocity of light in liquid and in air. Derive the formula of apparent depth of an object placed in liquid.
Explain the formation of the depletion layer at the p-n junction diode. Draw the characteristic curve of a reverse-biased junction diode showing Avalanche breakdown.
A concave lens has two surfaces of equal radii 30 cm and refractive index 1.5. Find its focal length.
What is meant by mass number of a nucleus? How is it different from atomic number?
The kinetic energy of a charged particle decreases by 10 joules as it moves from a point at potential 200 volt to a point at potential 250 volt. Find the charge on the particle.
Define work function. Write its unit.
Give an equation related to nuclear fusion.
In a Boolean expression \( Y = AB + BA' \), if \( A = 1 \), \( B = 1 \), then find the value of Y.
Show that N/C and V/m are the units of the same physical quantity. Name that physical quantity.
Write down two difficulties of Rutherford’s atomic model.
Find the energy stored in a capacitance of 10 μF when it is charged to a potential difference of 2 volts.
Mark out the correct option:
( If the energy of an atom in its ground state is -54.4 eV, then find its ionising potential.
Two ideal batteries of same emf (E₁ = E₂) and same internal resistance (r₁ = r₂) are connected in parallel. Their equivalent emf is E and internal resistance is r. The correct option is
Planck's constant has the same dimensions
When an impurity is doped into intrinsic semiconductor, the conductivity of the semiconductor
Let \(i_e\), \(i_c\), and \(i_b\) represent the emitter current, the collector current, and the base current respectively in a transistor then