Concave mirror is used in headlights of vehicles, because it 

A. focuses light from the bulb onto nearby vehicles 

B. sends parallel rays 

C. fits well into the shape of the headlight 

D. is cheaper than other mirrors

Melanin is the natural pigment that gives colour to human skin, hair and the iris. It provides protection against 

A. illtraviolet radiation 

B. Infrared radiation 

C. X-ray radiation 

D. Short wave radio radiation

Which one of the following statements about microbes is not correct? 

A. They are used in sewage treatment plants. 

B. They are used in industrial fermenters for the production of beverages. 

C. No antibiotic has been obtained from any microbe. 

D. They are used to get many bioactive molecules for the treatment of diseases.

Which one of the following is the scientific name of the causal organism of elephantiasis ? 

A. Ascaris lumbricoides 

B. Culex pipiens 

C. Wuchereria bancrofti 

D. Fasciola hepatica

Who among the following shared the Nobel Prize in 1962 along with Francis Crick and James Watson for their discoveries concerning the molecular structure of nucleic acids? 

A. Erwin Chargaff 

B. Maurice Hugh Frederick Wilkins 

C. Rosalind Franklin 

D. Phoebus Levene

Who among the following is the author of the book ‘The Indian Struggle, 1920- 1934? 

A. Maulana Abul Kalam 

B. Jayprakash Narayan 

C. Subhash Chandra Bose 

D. Manabendra Nath Roy

Which of the following statements about magnetite ore of iron is/are correct ? 

1. It is known as black ore. 

2. It contains 60% to 70% of pure iron. 

3. It possesses magnetic properties. 

Select the correct answer using the codes given below : 

A. 1 only 

B. 2 and 3 only 

C. 1 and 3 only 

D. 1,2 and 3

Which one among the following waves carries the maximum energy per photon? 

A. X-rays 

B. Radio waves 

C. Light waves 

D. Microwaves

How much CO₂ is produced on heating of 1 kg of carbon? 

A. 11/3kg

B. 3/11

C. 4/3kg

D. 3/4kg

Zinc is used to protect iron from corrosion because zinc is 

A. more electropositive than iron 

B. cheaper than iron 

C. a bluish white metal 

D. a good conductor of heat and electricity