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### Physics – Important Question Bank for Gujarat (12th std) HSC Board Exam 2020

Physics Important Question Bank 2020 (English Medium)

Height of TV tower is 102 m. If the average population density is 1000 / km2 , how many people can observe the programmes of this station? (Radius of the Earth = 6400 km)

The base current changes by 200 µA when a 200 mV signal is applied at the input of a CE amplifier. If the output voltage is equal to 2 volt, what is the voltage gain?

Write down points of comparison between an electric dipole and a magnetic dipole.

Calculate the quantum number for which the radius of the orbit of electron in Be3+ would be equal to that for the ground state of electrons in Hydrogen atom. Also compare the energy of the two states.

Derive Gaussian formula for concave mirror using appropriate figure.

When a linear object is placed in front of a convex mirror, image of the ¼ th size of object is formed. Calculate the object distance and the image distance. This linear object is kept perpendicular to the axis.

Write Biot Savart’s law and explain it.

A 1000 W bulb is kept at the centre of a spherical surface and is at a distance of 10 m from the surface.

Explain inductive components and radiated components with necessary diagram

Define Radio activity and obtain Exponential law for radio-active decay.

Two long solenoids are of equal length l and the smaller solenoid having crosssectional area a is placed within the larger solenoid in such a way that their axes coincide. Find the mutual inductance of the system.

Give first hypothesis of Bohr model and using it, derive expression for radius of the orbit of electron in Hydrogen atom.

An object is placed at a distance of 25 cm. on the axis of a concave mirror having focal length of 20 cm. Find the image distance, type of the image and its lateral magnification.

A battery having an emf epsilon and an internal resistance r is connected with a resistance R. Prove that the power in the external resistance is maximum when R=r.

Q amount of charge is uniformly distributed over some body. How should the body be divided into two parts, so that the force acting between the two parts is maximum for a given separation between them?

Write four characteristics of Photon.

What is Power Factor? Explain experimental arrangement of Hertz experiment with necessary diagram and show that it forms an oscillator circuit.

A circular coil having N turns is made from a wire of L meter length. If a current of I amp. is passed through the coil, which is suspended in a uniform magnetic field of B Tesla, find the maximum torque that can act on the coil.

Write any four properties attributed to a Photon as a result of Photoelectric and Compton Effect.

Write Kirchhoff’s First Law and obtain equation using necessary figure

What is called Inductor? Draw its Circuit symbol?

A magnetic pole with pole strength 100 Am is at 20 cm from a bar magnet has pole strength of 200 Am and has a length of 5 cm. If the magnetic pole is on the axis of the bar magnet, find the force on the magnetic pole.

For Fraunhoffer diffraction by a single slit, explain first maximum and derive the condition for first maximum.

Take the equation c5 = i + e – A for refraction of light due to a Prism, then derive equation for refractive index of the material of Prism.

Explain series combination of Capacitors and derive equation for the Resultant Capacitance in series combination.

A 900 pF capacitor is charged with the help of 100 V batteries. Calculate the steady electric energy on this capacitor. The above capacitor is disconnected from the battery and is connected to another identical capacitor. What will be the total energy of the system?

Explain Half Wave Rectification with necessary circuit diagram and graph.

Write limitations of Bohr model