thankyouJesus:
Area = 1X10⁷mm² = 1X10m².
P =20 Ohm/m.
L = 200cm = 2m.
R = PL/A.

thankyouJesus:
Classwork.
1. An electric lamp rated at 48w, 12v supply. Calculate the current flowing in the lamp and the resistance.

2. It takes 4minutes to boil a quantity of water electrically. How long will it take to boil same quantity of water using the same heating coil, but with the current doubled?

3. Calculate the amount of of heat generated in an external load of resistance 8 Ohm if an alternating current of peak value 5A is passed through it for 1min 40sec.

4. An electric heater takes 4A when operated on a 250V supply. What is the cost of the electricity consumed at 10k per kwh when the hate (heater?) is used for 5hours?

5. A man has a 40w and two 60w bulbs in a room. How much will it cost him to keep them lit for 8hours if the cost of a unit is 20kobo?

Dohyn3:
Can anyone direct me to the literature thread. please?
Been looking since...couldn't find it.
Anyone? Everyone?

Geofavor:
Orezy5, hop in here na. Can't you see it's getting cool and hot in here?

Geofavor:

eeyah. I don't think i've seen any one around. You can go to the jamb thread and ask. If there isn't, maybe someone would create one upon your request.

thankyouJesus:
Cc Geofavor.
1. Use this logic to correct question 4. If,
#100 = $1, similarly will,
#200 = $2, and also will,
#300 = $3.
Let me work with the first two, lets assume I am not aware of the conversion for #200. Let the conversion be x, therefore,
#100 = $1
#200 = x
cross multiply
100x = 200
divide both sides by 100, automatically,
x = $2.
Hint; if a unit is 10kwh, 1 = 10kwh.
2. There is a salient "two" in the question 5, check again.
I am loving your solution.

Geofavor:
thanks. I understand this logic.
the mistake i made was take 5 x 10 to be 15 instead of 50. Smh. I should be caned .

thankyouJesus:
Okay oga mi, check question 5 again for the two.Okay oga mi, check question 5 again for the two.

Dohyn3:

Thanks, i will...

Orezy5:
1. E=24V, r=4ohms, R=32ohms, I=?
E=I(R + r)
24=I(32 + 4)
24=36I
I=24/36
I=0.667A
The terminal p.d, V=Ir
V=0.667 X 4
V=2.668V



2. E=1.5V, r=?, R=3ohms, I=V/R=0.9/3=0.3A
E=I(R + r)
1.5=0.3(3 + r)
1.5=0.9 + 0.3r
0.3r= 1.5 - 0.9
0.3r=0.6
r=0.6/0.3
r=2ohms


3.
E=I(R + r)
lets form a simultaneous equation:

E=?, I=0.60A, R=2ohms, r=?
E=0.6(2 + r)
E=1.2 + 0.6r---------(i)
for the second equation,
E=?, I=0.30A, R=5ohms, r=?
E=0.30(5 + r)
E=1.5 + 0.30r---------(ii)
combine (i) with (ii)
E=1.2 + 0.6r
E=1.5 + 0.3r
To eliminate E, multiply (ii) by -1:
E=1.2 + 0.6r
-E= -1.5 - 0.3r
0= -0.3 + 0.3r
0.3r= 0.3
r=0.3/0.3
r=1ohm



4a.
when connected in parallel;
E=1.5V, I=?, R=5ohms, r=0.5ohm
E=I(R + r)
1.5=I(5 + 0.5)
1.5=5.5I
I=1.5/5.5
I=0.27A


4b.
when connected in series;
E=3V, I=?, R=5ohms, r=2ohms
E=I(R + r)
3=I(5 + 2)
3=7I
I=3/7
I=0.428A


Cc: thankyouJesus

muhamadnur:
thanks man we gat your back

thankyouJesus:
Good morning all, I want to assume most of you know this basic topics in Physics, lets move to more complex topics. To achieve this, could you drop a topic for me to write on taking into consideration my resumption date in UI.
Cc DebbyChris Oxytocin Geofavor Iceberryose Muhamadnur Orezy5

Geofavor:

welcome back sir.

Here,

PRESSURE

a) AtmosPheric Pressure
i) definition of atmosPheric Pressure
ii) units of Pressure
iii) measurement of Pressure
iv) simPle mercury barometer, aneroid barometer and manometer
v) variation of Pressure with height
vi) the use of barometer as an altmeter

b) Pressure in liquids
i) the relationshiP between Pressure, dePth and density (P = pgh)
ii) transmission of pressure in liquids ( pascal's principle)
iii) application.

mathefaro:
I hail thee my Oga for the wonderful with you're doing here. Although I'll suggest that questions should be asked and answered in details pertaining to the topic at hand instead of giving a kind of note. I'll be around to help henceforth when needed