Summary of physics formulas of the junior high school Beijing Normal University edition

Consider diverting your attention and thinking about something else worth thinking about.

1. Ohm's law part 1 i=u r (Ohm's law: the current in a conductor is proportional to the voltage at both ends of the conductor and inversely proportional to the resistance of the conductor) 2 i=i1=i2=....=in (the characteristic of the current in the series circuit: the current is equal everywhere) 3 u=u1+u2+....+un (characteristic of voltage in series circuits:

In a series circuit, the total voltage is equal to the sum of the voltages at both ends of each part of the circuit) 4 i=i1+i2+....+in (characteristic of the current in the parallel circuit: the current on the main circuit is equal to the sum of the currents of each branch) 5 u=u1=u2=....=un(Characteristics of voltage in parallel circuits: The voltage at both ends of each branch is equal.

are equal to the supply voltage) 6 r=r1+r2+....+rn (characteristic of resistance in series circuits: the total resistance is equal to the sum of the resistances of each part of the circuit) 7 1 r = 1 r1 + 1 r2 + ....+1 rn (characteristic of resistance in parallel circuits: the reciprocal of the total resistance is equal to the sum of the reciprocals of each parallel resistor) 8 r and = r n (the formula for finding the total resistance when n of the same resistor in parallel) 9 r string = nr (the formula for finding the total resistance when n of the same resistor in series) 10 u1:

u2=r1:r2 (the relationship between voltage and resistance in a series circuit: the ratio of voltage is equal to the ratio of resistance to which they correspond)11 i1:

i2 = R2: R1 (the relationship between current and resistance in parallel circuits: the ratio of current is equal to the inverse ratio of the resistance to which they correspond) 2. The electrical power part 12 P=UI (empirical, suitable for any circuit) 13 P=W T (defined, suitable for any circuit) 14 Q=I2RT (Joule's law, suitable for any circuit) 15 P=P1+P2+....+pn (suitable for any circuit) 16 w = uit (empirical, suitable for any circuit) composite formula, suitable only for pure resistance circuits) composite formula, only suitable for pure resistance circuits) empirical formula, only suitable for pure resistance circuits.

where w is the work done by the current flowing through the conductor, and q is the heat generated by the current flowing through the conductor) composite formula, which is only suitable for pure resistance circuits) Fuye Nian defective formula, only suitable for pure resistance circuits) 22 P1:P2=U1:U2=R1:

r2 (the relationship between electrical power and voltage and resistance in series circuits: in series circuits, the ratio of electrical power is equal to the ratio of voltage and resistance corresponding to them) 23 p1:p2=i1:

i2=r2:r1 (the relationship between electrical power and current and resistance in parallel circuits: in parallel circuits, the ratio of electrical power is equal to the ratio of the current corresponding to them, and equal to the inverse ratio of the resistance they correspond).