While performing experiments with pendulums, we take small angular amplitudes. Why

A student performed the experiment of heating ferrous sulphate crystals in a boiling tube. He smell fumes of a pungent gas saw colours of ferrous sulphate disappear Why does the colour of crystals disappear?

Two students X and Y performs an experiment on potentiometer separately using the ciruit diagram shown in the fig keeping other things unchanged X increases the value of resistance R. How would these changes affect the position of null point in each case and why?

Two students X and Y performs an experiment on potentiometer separately using the ciruit diagram shown in the fig keeping other things unchanged Y decreases the value of resistance S in the set up. How would these changes affect the position of null point in each case and why?

While swimming why do we feel light ?

The measurement of an unknown resistance R is to be carried out using wheatstone bridge(see Fig. EP 3.10). Two students perform an experiment in two ways. The first student takes R_2 = 10 Omega and R_1 = 5 Omega . The other student takes R_2 = 1000 Omega and R_1 = 500 Omega . In the standard arm, both takes R_3 = 5 Omega . Both find R = R_2/R_1 R_3 = 10 Omega within errors.

A student performs an experiment to study the magnetic effect of current around a current carrying straight conductor with the help of a magnetic compass. He reports that The direction of deflection of the magnetic compass increases when the current through the conductor is increased. Which of the above observations of the student appears to be wrong and why?

Bohr model is a system consisting of small, dense nucleus surrounded by orbiting electrons. The electrons travel is defined circular orbits around the nuclues which orbital angular moementum is an integral multiple of h/(2pi) . While rotating in allowed orbits (stationary orbits) the electron does not radiate energy. electromagnetic radiations are emitted when the electron jumps from a higher orbit (E_(ni)) to a lower orbit (E_(nf)) . The total energy of the electron in an atom is negative. It suggests that

Why does a motor take more current when we start it?