Which one of the following respiratory volumes of human lung is the lowest?
- A.Residual volume
- B.Tidal volume
- C.Inspiratory reserve volume
- D.Expiratory reserve volume
Correct answer
Explanation
The correct answer is B, Tidal volume. Tidal volume, the air breathed in or out in one normal quiet breath, is only about 500 millilitres in a healthy adult, the smallest of the four volumes listed. The other volumes are measured with a spirometer. Inspiratory reserve volume is the extra air that can be drawn in by a forceful breath after a normal inspiration, about 2,500 to 3,000 millilitres. Expiratory reserve volume is the extra air that can be pushed out forcibly after a normal expiration, about 1,000 to 1,100 millilitres. Residual volume is the air that stays in the lungs even after the most forceful expiration, about 1,100 to 1,200 millilitres, and it keeps the alveoli from collapsing. Option A is wrong because residual volume is more than twice the tidal volume. Option C is wrong because inspiratory reserve volume is the largest of these four. Option D is wrong because expiratory reserve volume is about twice the tidal volume. Exam tip: TV about 500 mL, ERV about 1,000 mL, RV about 1,200 mL, IRV about 2,500 to 3,000 mL; vital capacity = TV + IRV + ERV.
Practice Questions
View allWhich one of the following is not used as fertilizer?
- A.Ammonium nitrate
- B.Ammonium sulphide
- C.Ammonium phosphate
- D.Ammonium sulphate
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Ammonium sulphide is an unstable, foul-smelling compound that breaks down to release ammonia and toxic hydrogen sulphide, so it is not used as a fertiliser.
Read the full explanation →The focal length of the objective lens of a telescope is 50 cm. If the magnification of the telescope is 25, then the focal length of the eye-piece is
- A.12.5 cm
- B.5 cm
- C.2 cm
- D.10 cm
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For an astronomical telescope in normal adjustment the magnifying power equals the focal length of the objective divided by that of the eyepiece, so the eyepiece focal length is 50 ÷ 25 = 2 cm.
Read the full explanation →The major source of vitamins and minerals for vegetarians is
- A.black gram and wheat.
- B.rice and mustard.
- C.vegetables and fruits.
- D.soya bean and milk.
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Vegetables and fruits supply most of the vitamins and minerals in a vegetarian diet, which is why they are called protective foods.
Read the full explanation →Which one of the following compounds is used in black and white photography?
- A.AgF
- B.AgBr
- C.AgCl
- D.Ag2SO4
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Silver bromide is the light-sensitive compound coated on black and white photographic film and paper, because light breaks it down into tiny grains of silver metal.
Read the full explanation →Which one of the following statements about speed and velocity is correct?
- A.Speed and velocity both are vector quantities.
- B.Speed and velocity both are scalar quantities.
- C.Speed is vector quantity and velocity is scalar quantity.
- D.Speed is scalar quantity and velocity is vector quantity.
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Speed tells only how fast a body moves, while velocity also tells the direction of motion, and a quantity with both magnitude and direction is a vector.
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