class 10 physics

>A certain nucleus X has a mass number of 15 atomic number 7. Find the no. of neutrons. The nucleus X loses (i) one proton, (ii) one b - particle, (iii) one a - particle. Express each change and write a symbol of the new nucleus in each case. Suggested Answer:- No. of protons = mass no. - atomic no..

Note : One gram of hydrogen releases 6.2 x 10 10 J of energy where as one gram of coal produces 33 KJ of energy. Nuclear fusion takes place at a very high temperature which is equal to 4 x 10 6 o C. Fusion is the combination of two like light nuclei and the nu..

Case (i) Reflection occurring at a free end - In this case, there will be no reversal of phase due to reflection. Let the incident wave be represented by the equation The reflected wave will have the same amplitude, velocity and wavelength. It can be represented by The resultant displacement of the..

Whenever a ray of light passes through a lens (except when it passes through the optical center) it bends. The bending of light rays towards the principal axis is called convergence and bending of light rays away from the principal axis is called divergence. The degree of convergence or divergence..

Let us now perform an experiment and find out how light gets refracted when it is incident on a rectangular glass slab. Place a rectangular glass slab on a white sheet of paper fixed on a drawing board. Trace the boundary ABCD of the glass slab. Remove the glass slab. Draw an incident ray ..

Two waves are said to interfere destructively, if the resultant amplitude is minimum. This happens if Thus, the condition for destructive interference is that the path difference should be an odd multiple of half a waveleng..

"For a string of constant length and under a constant tension, the frequency of vibration is inversely proportional to the square root of its mass per unit length. If M is the mass and L is the length of the string, then If d is the diameter of the wire, then ..

In this case, there will be a reversal of phase due to reflection. Let the incident wave be represented by the equation. The reflected wave will have the same magnitude of the amplitude, velocity and wavelength. Due to reversal of phase (i.e., a crest returning as a trough or vice versa) the sign o..

In an open pipe, when a compressed wave reaches the far end, the air at that point is, for an instant, at a pressure greater than the atmospheric pressure. Being an open end, the air there can vibrate with maximum freedom and so, it suddenly expands into the surrounding air. Thus, the pressure dimi..

Potential difference is a measure of work done in moving a unit charge across a circuit. Current in a circuit is equal to the amount of charge flowing in one second. Therefore, the work done in moving 'Q' charges through a potential difference 'V' in a time 't' is given by Work done = potential dif..