Current definition formula I=Q/t Ohm's law I=U/R series circuit I=I 1=I2 parallel circuit I=I 1+I2.

Voltage series circuit U=U 1+U2 parallel circuit U=U 1=U2

Total resistance series r =R 1+R2 parallel r =R 1R2/(R 1+R2)

Definition of electric power P=W/t General formula P=UI

Definition of electric work W=UIt Known electric power W=Pt Known electric quantity W=UQ

Joule Law of Conductor Heat Q=I2Rt

Square of area S=a2 rectangle S=ab circle S=π(D/2)2

Volume cylinder V=Sh drainage method v solid =V2-V 1 cubic V=a3 submerged, v line =V object.

Speed definition v=s/t Average speed v=s total /t total.

Density definition ρ=m/V

Gravity G = mg

Buoyancy formula method F floating = ρ gV liquid row weighing method F floating =G-F' floating and hanging F floating =G Archimedes principle F floating = G row

Cause F float =F up -F sink down when f float = g-n.

Pressure definition formula p=F/S liquid interior p=ρgh

Power (mechanical) definition formula P=W/t Automobile power P=Fv

Work (mechanical) definition formula W=Fs total work w total =W useful +W quantity

Lever balance condition F 1l 1=F2l2

Force in the same direction F =F 1+F2 Force in the opposite direction F =F 1-F2 Pressure of objects on a horizontal table F=G Total pressure of liquid and gas F=pS.

Definition of mechanical efficiency η=W Useful /W Total lifting weight η=Gh/Fs Horizontal moving weight η=fs object /Fs

Hot fuel combustion Q=qm heat absorption and heat release q = cm δ t

Mechanical energy Mechanical energy = kinetic energy+potential energy

Q=U^/Rt

Q=I^Rt

=U\R (ohm's law) should be converted into u = ir.r = u \ i.

Voltage conversion; 1KV= 10 cubic 1mV= 10 negative cubic.

Series voltage uTotal =U 1+U2 parallel voltage uTotal =U 1=U2.

Resistance R= material density times (material length \ cross-sectional area)

1 mega-ohm = 10 to the 6th power ohm 1 kiloohm =10 to the 3rd power ohm.

Series resistance r = r 1+R2+R3+...+Rn parallel resistance.

One of R = one of R1+one of R2+... in Rn +Rn one.

power

1KW.h=3.6 times 10 to the sixth power.

W = 1/600 kwh

1KW= 10 cubic w

P=W\T (P= electric power, w is consumed electric energy and t is time)

P=UI

U real =U amount, P real =P amount, working normally.

U is less than u and p is less than p, so it can't work normally.

U is greater than u, p is greater than p, and it may burn out.

Q=I squared RT(Q= heat,)

For the convenience of calculation, when Q=W, Q=UIT (pure resistance only).

Of course, there is no formula for electricity and magnetism, but remember Ampere's Law. Hold the solenoid with your right hand and let your four fingers point to the direction of the current in the solenoid, then the end pointed by your thumb is the N pole of the solenoid. It is also necessary to find out what the strength of electromagnet magnetism is related to. How do speakers make sound? The function of magnetic field on live wires in motor, its basic structure, and the electromagnetic effect produced by magnetic field.