Answer:
a) the power consumption of the LEDs is 0.25 watt
b) the LEDs drew 0.0555 Amp current
Explanation:
Given the data in the question;
Three AAA Batteries;
<---- 1000mAh [ + -] 1.5 v ------1000mAh [ + -] 1.5 v --------1000mAh [ + -] 1.5 v------
so V_total = 3 × 1.5 = 4.5V
a) the power consumption of the LEDs
I_battery = 1000 mAh / 18hrs { for 18 hrs}
I_battery = 1/18 Amp { delivery by battery}
so consumption by led = I × V_total
we substitute
⇒ 1/18 × 4.5
P = 0.25 watt
Therefore the power consumption of the LEDs is 0.25 watt
b) How much current do the LEDs draw
I_Draw = I_battery = 1/18 Amp = 0.0555 Amp
Therefore the LEDs drew 0.0555 Amp current
PLEASE translate this question!
Answer:
Explanation:
Coefficient of performance (COP) of refrigeration cycle is given by:

We are given:


COP= 5
We can also write Coefficient of performance (COP) of refrigeration cycle as:

Amount of heat absorbed by low temperature reservoir can be found as:



According to first law of thermodynamics amount of heat rejected by hot reservoir is given by:



We are given the mass of 0.96 kg. So,



Since it is a saturated liquid-vapour mixture
.

From Refrigerant 134-a tables
at
is 61.3 C. (We calculated this by interpolation)
Converting
from Celsius to Kelvin:


We are given:




Converting
from Kelvin to Celsius:


From Refrigerant 134-a tables
at
is 356.9 KPa. (We calculated this by interpolation).