Answer:
As we are converting 220V AC into a 5V DC, first we need a step-down transformer to reduce such high voltage. Here we have used 9-0-9 1A step-down transformer, which convert 220V AC to 9V AC. In transformer there are primary and secondary coils which step up or step down the voltage according to the no of turn in the coils.
Selection of proper transformer is very important. Current rating depends upon the Current requirement of Load circuit (circuit which will use the generate DC). The voltage rating should be more than the required voltage. Means if we need 5V DC, transformer should at least have a rating of 7V, because voltage regulator IC 7805 at least need 2V more i.e. 7V to provide a 5V voltage.
Voltage (V)= Current (I) * Resistance (R)
I=V/R=140/2=70A
Hope this helps!
Answer:
A thermos bottle works well because:
A) Its glass walls are thin
Helium is lighter than air from the lungs.
Explanation:
A balloon filled with the air from lungs will sink to the ground but a balloon filled with Helium floats because helium is lighter than air.
Air is a mixture of many gases.
The air from the lungs is predominantly made up of carbon dioxide and water vapor.
- Gram per mole of carbon dioxide is 44. Water vapor is 18.
- Compared to helium which is 4, we see that the gas is lighter.
- Since the gas is lighter, it will float in air.
- The main component of air around us is nitrogen gas with a gram per mole of 28.
- A balloon filled with more of air from the lungs weigh more than that will filled air around and even far more than helium gas.
- This will cause a helium filled balloon to float.
learn more:
Density brainly.com/question/1698555
#learnwithBrainly
6 is b. part B on 6 is a. 7 is a. partB ON 7 b
