By what percentage will the illimination of the lamp decrease if the current drops by 20% ?

Determine the percentage by which the illumination of a lamp will decrease if the current drops by 20%.

Statement I : If the current of a lamp increases by 20 % , the percentage increases in the illlumination of the lamp is 40% . Statement II : Illumination of the lamp is directly proportional to the square of the current through the lamp.

Statement I : If the current of a lamp increases by 20 % , the percentage increases in the illlumination of the lamp is 40% . Statement II : Illumination of the lamp is directly proportional to the square of the current through the lamp.

If the price of petrol is increased by 20%,by what percentage should the consumption be decreased by the consumer, if the expenditure on petrol remains unchanged?

By what percentage should the length of a pipe, closed at one end, be increased or decreased, so that the fundamental frequency of the pipe decreases by 20% ?

By what percentage should the pressure of a given mass of a gas be increased so as to decrease its volume by 20% at a constant temperature?

By what percentage should the pressure of a given mass of a gas be increased so as to decrease its volume by 20% at a constant temperature?

if the electrc current in a lamp decreases by 5% then the power output decreases by

{:("Column A","A set has exactly five consecutive positive integers", "Column B"),("The percentage decrease in the average of the number when one of the numbers is dropped from the set",,20%):}