PUC Science 2nd PUC Class 12 - Karnataka Board PUC Important Questions

An electron, an alpha particle and a proton have the same kinetic energy.

Which one of these particles has the largest de-Broglie wavelength? 

The ground state energy of hydrogen atom is – 13∙6 eV. If an electron makes a transition from an energy level – 1∙51 eV to – 3∙4 eV, calculate the wavelength of the spectral line emitted and name the series of hydrogen spectrum to which it belongs.

Find out the wavelength of the electron orbiting in the ground state of hydrogen atom.

Find the wavelength of the electron orbiting in the first excited state in hydrogen atom.

The energy levels of an atom are as shown below. Which of them will result in the transition of a photon of wavelength 275 nm?

Which transition corresponds to emission of radiation of maximum wavelength?

Two nuclei have mass numbers in the ratio 1: 2. What is the ratio of their nuclear densities?

A radioactive nucleus ‘A’ undergoes a series of decays according to the following scheme:

The mass number and atomic number of A are 180 and 72 respectively. What are these numbers for A₄?

The radioactive isotope D decays according to the sequence

If the mass number and atomic number of D₂ are 176 and 71 respectively, what is (i) the mass number (ii) atomic number of D?

Derive an expression for voltage gain of the amplifier and hence show that the output voltage is in opposite phase with the input voltage.

In the following diagram 'S' is a semiconductor. Would you increase or decrease the value of R to keep the reading of the ammeter A constant when S is heated? Give reason for your answer.

State its any ‘two’ uses of photodiode.

Draw its I – V characteristics of photodiode

A zener diode is fabricated by heavily doping both p- and n- sides of the junction. Explain, why?

Explain briefly with the help of necessary diagrams, the forward biasing of a p-n junction diode. Also draw characteristic curves.

Explain briefly with the help of necessary diagrams, the  reverse biasing of a p-n junction diode. Also draw characteristic curves.

In the following diagram, is the junction diode forward biased or reverse biased ?

Write the functions of the three segments of a transistor.

The figure shows the input waveforms A and B for ‘AND’ gate. Draw the output waveform and write the truth table for this logic gate.

Explain the formation of depletion layer and potential barrier in a p−n junction.