Hydroponics Practice Questions
20 free Hydroponics practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Hydroponics refers to the cultivation of plants:
- A Without soil using nutrient solutions
- B In soil only
- C In open air only, without any growing medium
- D In dry sand
Correct answer: Without soil using nutrient solutions
Hydroponics is the method of growing plants without soil. Plants are supplied with nutrient solutions directly.
Which scientist is credited with developing hydroponics techniques?
- A Julius von Sachs
- B Darwin
- C Mendel
- D Justus von Liebig
Correct answer: Julius von Sachs
Julius von Sachs developed hydroponic culture techniques. He used nutrient solutions to grow plants.
In hydroponics, plants obtain nutrients from:
- A Air
- B Soil particles only
- C Nutrient solution
- D Sunlight
Correct answer: Nutrient solution
In hydroponics, nutrients are dissolved in water. Plants absorb them directly through roots.
Which of the following is essential in a nutrient solution?
- A Only macronutrients like nitrogen
- B Only micronutrients
- C Both macro and micronutrients
- D Only water
Correct answer: Both macro and micronutrients
Nutrient solutions must contain all essential elements. Both macro and micronutrients are required.
Which element is a macronutrient in plants?
- A Iron
- B Zinc
- C Nitrogen
- D Manganese
Correct answer: Nitrogen
Nitrogen is required in large amounts. It is essential for protein and nucleic acid synthesis.
Which of the following is a micronutrient?
- A Potassium
- B Phosphorus
- C Iron
- D Calcium
Correct answer: Iron
Iron is required in small amounts. It plays a role in chlorophyll synthesis and enzyme function.
What is the main advantage of hydroponics?
- A Needs a lot more land
- B Precise control of nutrients
- C Slower plant growth
- D Eliminates water usage entirely
Correct answer: Precise control of nutrients
Hydroponics allows precise control over nutrient supply. This improves plant growth and yield.
Which condition is necessary for hydroponic systems?
- A Dry soil for support
- B Adequate aeration of roots
- C High salinity levels
- D Complete absence of any light
Correct answer: Adequate aeration of roots
Roots require oxygen for respiration. Proper aeration is essential in hydroponic systems.
Which nutrient deficiency can be studied using hydroponics?
- A Deficiency of any nutrient
- B Only nitrogen deficiency alone
- C Only phosphorus deficiency
- D Only potassium deficiency
Correct answer: Deficiency of any nutrient
Hydroponics lets growers omit one nutrient at a time from the solution, so the deficiency symptoms caused by that specific nutrient can be observed in isolation. This kind of controlled, single-variable experiment is much harder to achieve in natural soil, which already contains a mix of nutrients.
Which of the following is NOT required in hydroponic systems?
- A Water
- B Nutrients
- C Soil medium
- D Oxygen supply
Correct answer: Soil medium
Hydroponics eliminates the need for soil. Nutrients are supplied in solution form.
Which element forms the central metal atom of the chlorophyll molecule?
- A Nitrogen (N)
- B Magnesium (Mg)
- C Iron (Fe)
- D Phosphorus (P)
Correct answer: Magnesium (Mg)
Magnesium sits at the centre of the porphyrin ring of every chlorophyll molecule, held there by four nitrogen atoms of the ring. Nitrogen is therefore part of chlorophyll too, but the central metal ion itself is magnesium, which is why magnesium deficiency shows up as interveinal chlorosis. Iron occupies the equivalent central position in haem.
Which factor must be monitored in nutrient solutions?
- A Soil texture
- B Solution pH
- C Wind speed
- D Sunlight only
Correct answer: Solution pH
pH affects nutrient availability. It must be maintained within an optimal range.
Which nutrient is required for root development?
- A Nitrogen
- B Phosphorus
- C Potassium
- D Calcium ion
Correct answer: Phosphorus
Phosphorus is important for root growth and energy transfer. It supports early plant development.
Which of the following is a common hydroponic medium?
- A Clay-rich garden soil
- B Coarse beach sand only
- C Perlite or gravel
- D Wet garden mud
Correct answer: Perlite or gravel
Perlite and gravel are used as support media. They provide anchorage without supplying nutrients.
Which nutrient helps in stomatal regulation?
- A Nitrogen
- B Phosphorus
- C Potassium
- D Iron
Correct answer: Potassium
Potassium regulates stomatal opening and closing. It controls water balance in plants.
Which element is part of amino acids?
- A Calcium
- B Nitrogen
- C Potassium
- D Iron
Correct answer: Nitrogen
Nitrogen is a component of amino acids. It is essential for protein synthesis.
Which nutrient deficiency causes interveinal chlorosis in young leaves?
- A Nitrogen
- B Potassium
- C Phosphorus
- D Iron (Fe)
Correct answer: Iron (Fe)
Iron is essential for chlorophyll synthesis, and because it is immobile within the plant, its deficiency causes interveinal chlorosis (yellowing between the veins) specifically in young leaves. Nitrogen deficiency, by contrast, is mobile and causes uniform yellowing that starts in older leaves.
Which of the following is a benefit of hydroponics in agriculture?
- A Significantly lower yield
- B More soil erosion
- C Reduced nutrient control
- D Efficient water use
Correct answer: Efficient water use
Hydroponics uses water efficiently. It reduces wastage and improves productivity.
Which nutrient is essential for ATP formation?
- A Nitrogen
- B Calcium ion
- C Iron (Fe)
- D Phosphorus
Correct answer: Phosphorus
Phosphorus is a component of ATP. It is vital for energy transfer in cells.
Which of the following best describes hydroponics?
- A Growing plants in air with mist
- B Growing plants in sand with water
- C Growing plants in dry soil only
- D Growing plants in nutrient water
Correct answer: Growing plants in nutrient water
Hydroponics involves growing plants in water enriched with nutrients. Soil is not required.