The brightness of the lamp is proportional to the current flowing through the lamp: the larger the current, the brighter the lamp.
The current flowing through the lamp is given by Ohm's law:

where
V is the potential difference across the lamp, which is equal to the emf of the battery, and R is the resistance of the lamp.
The problem says that the battery is replaced with one with lower emf. Looking at the formula, this means that V decreases: if we want to keep the same brightness, we need to keep I constant, therefore we need to decrease R, the resistance of the lamp.
Answer:
Difference between heat and temperature in tabular form
Heat vs Temperature
1.Heat is a form of energy that can transfer from a hot body to a cold body. and Temperature is the degree of hotness and coldness of a body.
2.Heat is the total kinetic energy and potential energy obtained by molecules in an object. and Temperature is the average K.E of molecules in a substance.
3.Heat flows from hot body to cold body. It rises when heated and falls down when an object is cooled down and It has a working ability. It does not have the working ability
.
4.Its SI unit is “Joule” and Its SI unit is “Kelvin”.
5.It is measured by the calorimeter and It is measured by the thermometer
.
6.It is represented by “Q”. and It is represented by “T”.
Explanation:
A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. ... A simple calorimeter just consists of a thermometer attached to a metal container full of water suspended above a combustion chamber.
A reversible change is a change that can be undone or reversed
Answer:
Destructive interference
Explanation:
Destructive interference occurs when waves come together in such a way that they completely cancel each other out. When two waves interfere destructively, they must have the same amplitude in opposite directions.