A transformer is used to produce a mains voltage of 230V for a house. There are 2000 turns on the primary coil and 20 turns on the secondary coil. What voltage must the power lines have supplied to this transformer?

2.3 volts

Explanation:

The transformer turns ration is calculated by dividing the number of turns in the primary coil by the number of turns in the secondary coil.

Mathematically;  

This ratio is equal to voltage of primary winding divided by the voltage of the secondary winding. i.e.

This means you can combine the two equations as;

Given that;

Substitute the values in the equation as;

2000/20 =230/Vs

Vs=230/100

Vs=2.3 v

i think it'll be 7,000

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this