Cosmetology Chemistry & Electricity Practice Questions
Chemistry & Electricity makes up 4 of every 50 questions on a Tigertest Cosmetology practice test. Here are 10 of the 16 questions on it, each with the answer and the reason.
Updated by the Tigertest team. These sets follow the NIC theory exam only: 110 items, 100 scored, 90 minutes (outline effective July 1, 2022). PSI states, including California from April 1, 2026, use a 120-minute outline. This bank is not weighted to PSI.
1. What is the natural pH range of hair and skin?
- A.8.0 to 9.0
- B.4.5 to 5.5
- C.7.0 to 7.5
- D.2.5 to 3.5
Answer: B. The acid mantle keeps hair and skin slightly acidic, around 5. Products near that range keep the cuticle flat; alkaline products open it.
2. A product with a pH of 7 is:
- A.Mildly alkaline
- B.Strongly acidic
- C.Mildly acidic
- D.Neutral
Answer: D. Pure water is 7, the midpoint of the 0 to 14 scale. Anything below 7 is acidic and anything above is alkaline.
3. Each whole number on the pH scale represents a change of how much?
- A.Ten times
- B.Five times
- C.Two times
- D.One hundred times
Answer: A. The scale is logarithmic, so a pH of 9 is ten times more alkaline than 8 and a hundred times more alkaline than 7.
4. What does an alkaline product do to the hair cuticle?
- A.Dissolves it
- B.Has no effect on it
- C.Swells and opens it
- D.Contracts and closes it
Answer: C. Alkaline solutions raise the cuticle scales so chemicals can reach the cortex. Acidic solutions close and harden it, which is why conditioners are acidic.
5. When hydrogen peroxide releases oxygen in haircolor or a neutralizer, the reaction is:
- A.Neutralization
- B.Emulsification
- C.Oxidation
- D.Reduction
Answer: C. Oxidation adds oxygen (or removes hydrogen) and is the reaction that develops color and rebuilds disulfide bonds. Reduction is the opposite, as in perm waving lotion.
6. A mixture of two liquids that do not normally mix, held together by an emulsifier, is:
- A.An emulsion
- B.A suspension
- C.A compound
- D.A solution
Answer: A. Creams and lotions are emulsions of oil and water. A solution is fully dissolved, a suspension settles out, and a compound is chemically bonded.
7. Most salon creams and lotions are which type of emulsion?
- A.Silicone-in-oil
- B.Water-in-oil
- C.Alcohol-in-water
- D.Oil-in-water
Answer: D. Oil-in-water emulsions have tiny oil droplets in a water base, feel light and rinse easily. Water-in-oil emulsions are heavier, like cold cream.
8. The water-loving end of a surfactant molecule is called:
- A.Oleophilic
- B.Hydrophilic
- C.Lipophilic
- D.Hydrophobic
Answer: B. A surfactant has a hydrophilic head that attaches to water and a lipophilic (hydrophobic) tail that attaches to oil, which is how it lifts oil off hair.
9. Electric current that flows in one direction only is:
- A.Tesla current
- B.Direct current
- C.Alternating current
- D.Faradic current
Answer: B. Direct current (DC), as in batteries and galvanic devices, flows one way. Alternating current (AC) from wall outlets reverses direction many times a second.
10. Which device shuts off power when current leaks to ground, as near a shampoo bowl?
- A.A fuse box
- B.A surge protector
- C.A circuit breaker
- D.A GFCI outlet
Answer: D. A ground fault circuit interrupter senses a current leak and cuts power in a fraction of a second, preventing shock around water. Breakers and fuses protect against overloads, not leaks.
Practice all 16 chemistry & electricity questions, and the rest of the 200-question bank, in the free Cosmetology training sets. Questions you miss come back until you have mastered them.
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