Power (P) = 250 W

Voltage (V) = 230 V

(i) We know that,

W (energy consumed) = P×t

Given, t= 1h

Covert the hour into seconds since Joule = watt×sec

t=60×60 seconds

= 3600 seconds.

Now,

W= P×t

= 250×3600

= 9 × 100000 J

(ii) we know,

Energy (in kWh) = (V×Ixt)/1000

We don't have I (Ampere), therefore

I = P/V

= 250/230 A

= (Lets just keep it this way) 25/23 A

Now, given energy = 1 kWh

1 kWh= (230×25xt)/1000×23

=> (1000×23)/230×25= t

=> 4 hours = t

Calculation of Energy Consumption

To calculate the energy consumption of an electric bulb, we need to use the formula:

Energy (in Joules) = Power (in Watts) * Time (in seconds)

Given that the bulb is marked as 250 W (watts), we can calculate the energy consumption in 1 hour (3600 seconds) as follows:

Energy = 250 W * 3600 s

Converting Watts to Joules

Since the unit of power is given in Watts and we need to calculate the energy in Joules, we need to convert the unit. The conversion factor between Watts and Joules is:

1 Watt = 1 Joule/second

This means that 1 Watt of power is equivalent to 1 Joule of energy consumed per second. Therefore, the energy consumption can be written as:

Energy = (250 W * 3600 s) * (1 J/s)

Calculating Energy Consumption

Using the formula for energy consumption, we can substitute the given values:

Energy = 250 W * 3600 s * (1 J/s)

Simplifying the equation gives us:

Energy = 900,000 J

Therefore, the electric bulb consumes 900,000 Joules of energy in 1 hour.

Calculating Time to Use 1 kWh of Energy

To calculate the time it takes for the lamp to use 1 kWh of energy when connected to a 230 V mains, we can use the formula:

Energy (in kWh) = Power (in kW) * Time (in hours)

Given that the bulb is connected to a 230 V mains, we can calculate the time as follows:

Energy = 1 kWh = 1000 Wh

Converting Wh to Joules:

1 Wh = 3600 J

Therefore, 1000 Wh = 1000 * 3600 J = 3,600,000 J

Using the formula for energy consumption, we can calculate the time:

3,600,000 J = 250 W * Time (in seconds)

Simplifying the equation gives us:

Time = 3,600,000 J / 250 W = 14,400 seconds

Converting the time from seconds to hours:

Time = 14,400 s / 3600 s = 4 hours

Therefore, the lamp would take 4 hours to use 1 kWh of energy when connected to a 230 V mains.