The rated voltage of the electric pan is 220 V, the upper and lower plates are heated at the same time to make the rated power 1000 W, s is the main switch, S1 and S2 are two temperature control switches, R1 and R2 are the heating resistors of the upper and lower panels, R1 = R2. When R1 works normally, what is the electric power consumed by R1? When R1 works normally, what is the current passing through R1?

The power of R1 is 500W, and the current passing through R1 is 500 / 220 = 2.27a

39 out of 50 minus 1 out of 2 minus 1 out of 3 minus 1 out of 6 =?

39 out of 50 minus 1 out of 2 minus 1 out of 3 minus 1 out of 6
=39 out of 50 minus (1 out of 2 + 1 out of 3 + 1 out of 6)
=39 out of 50 minus 1
=11 out of 50

At present, a "220 V 100 W" incandescent lamp is connected to the home circuit with a long wire. The actual power consumed by the bulb is only 81 watts, so the resistance of the long wire is low
At present, a "220 V 100 W" incandescent lamp is connected to the home circuit with a long wire. The actual power consumed by the bulb is only 81 watts, so the resistance of the long wire is ()
A．484Ω B．121Ω C．53.8Ω.D．9Ω

The equivalent resistance of the bulb is r = u and 178 / P = 220 and 178 / 100 = 484 Ω
The actual power consumption is 81w, so the partial voltage is PR = 198v under u = root
Therefore, the conductor resistance is 484 × (220-198) △ 198 = 53.8 Ω

Simple calculation: 0.625 × 0.5 + 5 / 8 + 1 / 2 × 62.5%

=0.625*（0.5+1+0.5）
=1.25

Two resistors with R1 = 5 ohm and R2 = 10 ohm are connected in series in the circuit. Their total resistance is [] ohm, and the ratio of voltage at both ends of R1 to voltage at both ends of R2 is []

15 ohm, 1:2

A simple algorithm of 18 times 125

18x125
=(10+8)x125
=10x125+8x125
=1250+1000
=2250

There is an ammeter g with internal resistance Rg = 30 Ω and full bias current Ig = 1mA. How to refit it into a voltmeter with a range of 0 ~ 3V?
What is the resistance of the refit?
There is one step in the analysis process: ur (voltage divided by series resistor) = u-ug = 2.97v
The title does not say how much u is, how can we calculate ur (the voltage divided by series resistance) = u-ug = 2.97v this step!

UG is the full bias voltage of the meter, UG = Ig * RG = 0.001 * 30 = 0.03V
The voltage ur = u-ug = 3-0.03 = 2.97v. U is the full range 3V of the modified voltmeter
Series connection resistance RX = ur / Ig = 2.97 / 0.001 = 2970 Ω is required

3 / 4 △ [3 / 5 + 2 / 5 × (3 / 1-8)]

(3/4)÷[3/5+2/5×(1-3/8)] =(3/4)÷(3/5+1/4) =5/4+3 =17/4

How do you read these unit symbols
The unit of molar mass is g / mol, read as: gram per mole. It can also be g.mol-1 (. Is the middle - 1, is the top right of mol)?
How to read 12C (C is carbon, 12 is on the top left of C)
Do g / mol and g.mol-1 read as grams per mole?

Front
G / mol
The one in the back is carbon 12
G / mol and g.mol-1 are the same thing
It's written differently
The reading is the same

I would like to ask the elderly walking with crutches more stable and not easy to fall down, what is the method to increase stability?

Stability can be increased by increasing the force area of human body on the ground