In order to calculate the units of energy consumed by the lamp, we need to understand the concept of watt and unit.

Watt (W) is a unit of power, which represents the rate at which energy is consumed. The higher the wattage, the more power it consumes.

Unit (kWh) is a unit of energy, which represents the total amount of electricity consumed over a period of time.

In this case, the lamp has a power rating of 100 watts and is used for 10 hours per day. To calculate the units of energy consumed, we need to convert the power rating from watts to kilowatts (kW) by dividing it by 1000.

So, the lamp consumes 0.1 kilowatts (100 watts / 1000) of power.

To find the total energy consumed in one day, we multiply the power consumption by the duration of usage.

0.1 kilowatts x 10 hours = 1 kilowatt-hour (kWh)

Therefore, the units of energy consumed in one day by the lamp is 1 unit.

Note: In some regions, the term "unit" is used interchangeably with "kilowatt-hour" (kWh).