Chemical Safety and Physics Quiz

Concentration in parts per million (ppm) is calculated by multiplying milligrams per cubic meter (mg/m³) by 24.45 and dividing by the molecular weight (MW) of the substance.

The Time Weighted Average (TWA) is the average concentration of a chemical over a specific period. It is calculated by summing the products of each concentration (C) and its corresponding exposure time (T), then dividing by the total exposure time.

The Lower Flammable Limit (LFL) is the lowest concentration of a gas or vapor in air that will support combustion. It's calculated by inverting the sum of the fractions of each component's LFL.

The Threshold Limit Value (TLV) is the airborne concentration of a substance that most workers can be exposed to daily without adverse effects. It's similarly computed by inverting the sum of fractions of each component's TLV.

The combined gas law combines Charles's Law and Boyle's Law to relate pressure, volume, and temperature. The formula states that the product of the initial pressure and volume divided by temperature is equal to the product of the final pressure and volume divided by temperature, provided the gas remains constant.

The electrical formula V = IR relates voltage (V), current (I), and resistance (R). Voltage is simply the potential difference between two points, current is the flow of charge, and resistance opposes this flow.

Electrical power (P) is the rate at which energy is transferred. It's calculated by multiplying voltage (V) and current (I) or by squaring current (I) and multiplying by resistance (R).

The amount of radiation remaining after a certain time has passed. Measured in units of activity (e.g., Becquerels, Curies).

The original amount of radioactivity at the start of the decay process.

Time elapsed since the start of radioactive decay.

A constant that describes how quickly a radioactive substance decays.

The time it takes for half of the radioactive material to decay.

The amount of radioactive material that remains after a certain time has elapsed and can be calculated using the half-life.

The original amount of radioactivity at the start of the decay process.

The measure of the rate of flow of a fluid through a duct.

The pressure created by the movement of a fluid. It is the pressure difference between two points in a flowing fluid, caused by its velocity.

The centerline velocity of air entering a hood, measured in feet per minute (fpm), at a point 'x' feet directly in front of the hood opening.

The distance from the hood opening to the point where you're measuring capture velocity, measured in feet (ft).

The area of the hood opening, measured in square feet (ft²).

The formula used to calculate capture velocity for hoods without flanges.

The formula used to calculate capture velocity for hoods with flanges.

A measure of the overall heat stress experienced, taking into account air temperature, humidity, and radiation.

The temperature measured with a thermometer covered with a wet wick.

The temperature measured with a black globe thermometer, which absorbs radiant heat.

A measure of sound power, expressed in decibels (dB).

The probability of an event occurring within a specific time period, calculated using the Poisson distribution.

The expected number of events occurring in a given time period or interval.

The coefficient of correlation, a measure of the strength and direction of the linear relationship between two variables.

The sample standard deviation, a measure of the spread or variability of a sample of data.

A statistical measure that indicates how many standard deviations a data point is away from the mean.

The probability of a system functioning without failure for a specified time period.

The number of combinations possible when taking a certain number of things from a larger set. Calculated using the factorial function.

The number of observed events or the rate at which events occur.

The pressure drop per unit length of a pipe due to friction.

The force per unit area exerted by a fluid at rest.