In a television set the power needed to operate the picture tube comes from the secondary of a transformer. the primary of the transformer is connected to a 120-v receptacle on a wall. the picture tube of the television set uses 91 w, and there is 5.5 ma of current in the secondary coil of the transformer to which the tube is connected. find the turns ratio ns/np of the transformer.

  138 for the ratio Ns/Np

Explanation: In order to explain this question we have to take into account the relationship for transformer wichi os given by ;

Vs=Vp Ns/Np where Vs and Vp are the voltage corresponding to the secondary and primary coil of the transformer, respectively. Ns and Np are the turns for the secondary and primery coil , respectively.

Firsly  we have to calculate Vs which is given by power (91W) and current (5.5 mA) used. Then

Ps=Is*Vs=

Vs=91W/5.5 mA=16.54 *10^3 V so

Vs/Vp=Ns/Np

Ns/Np=16.54*10^3/120=138

e) none of the above answers are correct

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz