## IB Physics Glossary

Browse the glossary using this index

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**S**| T | U | V | W | X | Y | Z | ALL

## S |
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## Satellite paradox occurs when a satellite moves into a low orbit such that the frictional force increases the speed of the satellite.
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## Scalar multiplication of vectors, changes the magnitude of the vector but not the direction. For scalar $$a$$ and vector $$\vec{A}$$ with x- or horizontal component $$A_H=A \cos \theta$$ y- or vertical compnonet $$A_V= A \sin \theta$$ magnitude $$A=\sqrt{A_H^2 + A_V^2}$$ The multiplication $$a \times \vec{A}$$ has magnitude $$a \times A$$. The division $$\vec{A} \div a$$ has magnitude $$A \div a$$. | |

## Scalar quantities have magnitude only. Direction or changes in direction have no effect on scalar quantities. Examples include distance, speed, mass and temperature. | |

## SchĂ¶nberg-Chandrsekhar limit states, a star leaves the main sequence when it consumes about 12% of its hydrogen fuel. (d) | |

## Schwarzchild radius is the distance from the centre of a black hole at which the escape velocity is equal to the speed of light in empty space, c. The radius can be found using $$R= R_s = \frac{2GM}{c^2}$$ where G is the gravitational constant, M is the mass of the black hole and c is the velocity of light in empty space. | |

## Scotopic vision is black and white vision which occurs in low-light conditions. Vision is aided by the rod cells. Cone cells don't play a role. | |

## Second law of thermodynamicsstates that thermal energy cannot spontaneously transfer from a region of low temperature to a region of high temperature or the total entropy of the universe must always stay the same or increase. | |

## Secondary colors are Cyan (Blue & Green), Magenta (Blue & Red) and Yellow (Green and Red). | |

## Sensory hearing loss occurs when the air conduction thresholds (middle ear) and the bone conduction thresholds (cochlea) both show a hearing losses. If bone conduction losses are greater than a cochlea implant may be required. Reasons include - ageing;
- prolonged exposure to excessive noise.
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## Signifiant figuresa rule, the number of significant digits in a result should not exceed that of the least precise value upon which it depends. | |