Atoms — Physics STD 12 Science — Question

Calculate the potential energy of a single charge in an external field.

Write the definition of electrostatic potential. Tell whether it is a vector or a scalar quantity ? Also write its SI unit and dimensional formula.

If we put a cardboard (say 20cm × 20cm) between a light source and our eyes, we can't see the light. But when we put the same cardboard between a sound source and our ear, we hear the sound almost clearly. Explain.

The given inputs A and B are fed to 2-inputs NAND gate. Draw the output waveform of the gate.

A ball is projected from a point on the floor with a speed of 15m/s at an angle of 60° with the horizontal. Will it hit a vertical wall 5m away from the point of projection and perpendicular to the plane of projection without hitting the floor? Will the answer differ if the wall is 22m away?

Draw a circuit diagram using a metre bridge and write the necessary mathematical relation used to determine the value of an unknown resistance. Why cannot such an arrangement be used for measuring very low resistances?

Give brief explanation of modern solid state semi-conductor electronics.

A block of mass m containing a net positive charge q is placed on a smooth horizontal table which terminates in a vertical wall as shown in figure. The distance of the block from the wall is d. A horizontal electric field E towards right is switched on. Assuming elastic collisions (if any) find the time period of the resulting oscillatory motion. Is it a simple harmonic motion?