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Board Exams 2022
Education Blogs
Class 12 Business studies Exam Today’s Term 2 Question Paper & Answer Key

The CBSE class 12 Business studies term 2 exam has different reactions coming in from students who …

komal
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(a) Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves. (b) If the Earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now? Explain. (c) An e.m. wave exerts pressure on the surface on which it is incident. Justify.
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(a) Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves. (b) If the Earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now? Explain. (c) An e.m. wave exerts pressure on the surface on which it is incident. Justify.

(a) Name the e.m. waves which are suitable for radar systems used in aircraft navigation. Write the…

komal
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The focal length of a convex lens made of glass of refractive index (1.5) is 20 cm. What will be its new focal length when placed in a medium of refractive index 1.25 ? Is focal length positive or negative? What does it signify?
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The focal length of a convex lens made of glass of refractive index (1.5) is 20 cm. What will be its new focal length when placed in a medium of refractive index 1.25 ? Is focal length positive or negative? What does it signify?

The focal length of a convex lens made of glass of refractive index (1.5) is 20 cm. What will be it…

komal
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Light of wavelength 2000 Å falls on a metal surface of work function 4.2 eV. (a) What is the kinetic energy (in eV) of the fastest electrons emitted from the surface? (b) What will be the change in the energy of the emitted electrons if the intensity of light with same wavelength is doubled? (c) If the same light falls on another surface of work function 6.5 eV, what will be the energy of emitted electrons?
Education Blogs
Light of wavelength 2000 Å falls on a metal surface of work function 4.2 eV. (a) What is the kinetic energy (in eV) of the fastest electrons emitted from the surface? (b) What will be the change in the energy of the emitted electrons if the intensity of light with same wavelength is doubled? (c) If the same light falls on another surface of work function 6.5 eV, what will be the energy of emitted electrons?

Light of wavelength 2000 Å falls on a metal surface of work function 4.2 eV. (a) What is the kineti…

komal
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(a) Draw a ray diagram of Astronomical Telescope for the final image formed at infinity. (b) A small telescope has an objective lens of focal length 140 cm and an eyepiece of focal length 5.0 cm. Find the magnifying power of the telescope for viewing distant objects when (i) the telescope is in normal adjustment, (ii) the final image is formed at the least distance of distinct vision.
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(a) Draw a ray diagram of Astronomical Telescope for the final image formed at infinity. (b) A small telescope has an objective lens of focal length 140 cm and an eyepiece of focal length 5.0 cm. Find the magnifying power of the telescope for viewing distant objects when (i) the telescope is in normal adjustment, (ii) the final image is formed at the least distance of distinct vision.

(a) Draw a ray diagram of Astronomical Telescope for the final image formed at infinity. (b) A smal…

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(a) Draw a ray diagram of compound microscope for the final image formed at least distance of distinct vision? (b) An angular magnification of 30X is desired using an objective of focal length 1.25 cm and an eye piece of focal length 5 cm. How will you set up the compound microscope for the final image formed at least distance of distinct vision?
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(a) Draw a ray diagram of compound microscope for the final image formed at least distance of distinct vision? (b) An angular magnification of 30X is desired using an objective of focal length 1.25 cm and an eye piece of focal length 5 cm. How will you set up the compound microscope for the final image formed at least distance of distinct vision?

(a) Draw a ray diagram of compound microscope for the final image formed at least distance of disti…

komal
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Define wavefront. Draw the shape of refracted wavefront when the plane incident wave undergoes refraction from optically denser medium to rarer medium. Hence prove Snell’s law of refraction.
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Define wavefront. Draw the shape of refracted wavefront when the plane incident wave undergoes refraction from optically denser medium to rarer medium. Hence prove Snell’s law of refraction.

Define wavefront. Draw the shape of refracted wavefront when the plane incident wave undergoes refr…

komal
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How long can an electric lamp of 100 W be kept glowing by fusion of 2 kg of deuterium? Take the fusion reaction as
Education Blogs
How long can an electric lamp of 100 W be kept glowing by fusion of 2 kg of deuterium? Take the fusion reaction as

How long can an electric lamp of 100 W be kept glowing by fusion of 2 kg of deuterium? Take the fus…

komal
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Explain with a proper diagram how an ac signal can be converted into dc ( pulsating)signal with output frequency as double than the input frequency using pn junction diode. Give its input and output waveforms.
Education Blogs
Explain with a proper diagram how an ac signal can be converted into dc ( pulsating)signal with output frequency as double than the input frequency using pn junction diode. Give its input and output waveforms.

Explain with a proper diagram how an ac signal can be converted into dc ( pulsating)signal with out…

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Derive an expression for the frequency of radiation emitted when a hydrogen atom de-excites from level n to level (n – 1). Also show that for large values of n, this frequency equals to classical frequency of revolution of an electron.
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Derive an expression for the frequency of radiation emitted when a hydrogen atom de-excites from level n to level (n – 1). Also show that for large values of n, this frequency equals to classical frequency of revolution of an electron.

Derive an expression for the frequency of radiation emitted when a hydrogen atom de-excites from le…

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Name the device which converts the change in intensity of illumination to change in electric current flowing through it. Plot I-V characteristics of this device for different intensities. State any two applications of this device.
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Name the device which converts the change in intensity of illumination to change in electric current flowing through it. Plot I-V characteristics of this device for different intensities. State any two applications of this device.

Name the device which converts the change in intensity of illumination to change in electric curren…

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Explain how does (i) photoelectric current and (ii) kinetic energy of the photoelectrons emitted in a photocell vary if the frequency of incident radiation is doubled, but keeping the intensity same? Show the graphical variation in the above two cases.
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Explain how does (i) photoelectric current and (ii) kinetic energy of the photoelectrons emitted in a photocell vary if the frequency of incident radiation is doubled, but keeping the intensity same? Show the graphical variation in the above two cases.

Explain how does (i) photoelectric current and (ii) kinetic energy of the photoelectrons emitted in…

komal
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