# Formulas not in Formula Book / OCR AS Physics B (Advancing Physics)

A guide to some essential formulas for use in the OCR Physics B (Advancing Physics) AS-Level Exam. I've only included the ones which aren't in the formula booklet.

A2 one coming soon.

- Created by: Matty
- Created on: 05-05-12 15:25

First 334 words of the document:

Formulas Not In Formula Booklet

To Calculate... Do... Units...

LENSES (P1) (Paper One)

Magnification v/u image height / object height None

Power 1 / frequency D, dioptres

SIGNALLING (P1)

Number of Bytes Number of Bits / 8 bytes

Number of Alternative Levels 2number of bits None

Number of Bits log2(Number of Alternative Levels) bits

Minimum Rate of Sampling 2 x maximum frequency of signal Hz (or s-1)

Rate of Transmission samples per second x bits per sample bits s-1

Bandwidth 1 / (time that 1 bit is on)

Bandwidth Maximum number of bits per second Hz

Bandwidth is the same as carrier frequency

SENSING (P1)

(emf) terminal p.d. + lost p.d. V

Current x (Circuit Resistance + Internal Resistance) V

Rearrange those to get to the other equations. There is one in the formula booklet, so you can rearrange

that instead, if you forget these.

R1 has R1 / (R1 + R2) of the total resistance. Multiply this by the voltage of Ohms

the input (cell, battery or AC supply) to find the voltage across R1.

Work Power x time W

Work Voltage x Current x time W

MATERIALS (P1)

All formulas for Materials are in the formula booklet.

WAVE BEHAVIOUR (P2) (Paper Two)

Path Difference

- Destructive Inteference (n + ½) (where the waves meet ½ out of phase) None just an

occurs when: indicator of how

the waves meet

- Constructive Inteference n (where the waves meet in phase, a (constructive or

occurs when: integer multiple of apart, eg 1, 4, 6 etc) destructive)

Double Slit Formula:

X is the distance between two maximas or two minimas formed on the wall (Fringe Spacing)

D is the distance between the slits and wall, d is the distance between the slits

Fringe Spacing, X (D) / d m

This formula is the same as dsin = n, but

relies on being small

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