Magnetism And Matter — Physics STD 12 Science — Question

A block of known mass is suspended from a fixed support through a light spring. Can you find the time period of vertical oscillation only by measuring the extension of the spring, when the block is in equilibrium?

A glass lens of refractive index 1.5 is placed in a trough of liquid. What must be the refractive index of the liquid in order to make the lens disappear?

Draw graphs showing variation of photoelectric current with applied voltage for two incident radiations of equal frequency and different intensities. Mark the graph for the radiation of higher intensity.

Define the term 'electrical conductivity' of a metallic wire. Write its S.I unit.

Which part of electromagnetic spectrum is used in satellite communication?

A resistor, inductor and a capacitor are joined with a de source. What is the magnitude of impedance of the circuit?

What is called equipotential surface?Draw the diagram of equipotential surface due point positive charge.

An electric lamp and a candle produce equal illuminance at a photometer screen when they are placed at 80cm and 20cm from the screen respectively. The lamp is now covered with a thin paper which transmits 49% of the luminous flux. By what distance should the lamp be moved to balance the intensities at the screen again?