Home
Class 12
BIOLOGY
The material generally used for sound pr...

The material generally used for sound proffing of rooms like a recording studio and auditorium, etc. is

A

cotton

B

coir

C

wood

D

styrofoam.

Text Solution

Verified by Experts

The correct Answer is:
D
Promotional Banner

Similar Questions

Explore conceptually related problems

What are the materials used to grow microorganism like Spirulina?

Assertion : At high altitude a person, from plain areas, may experience altitude sickness. Reason : At high altitude atmospheric pressure is generally high leading to symptons like nausea, fatigue, etc.

Read the following statements and select the correct option. Statement 1 : Many fungi beionging to genera Microsporum, Trichophyton and Epidermophyton are responsible for the disease ringworm. Statement 2 : Ringworm infection is generally acquired from soil or by using towels, clothes, comb, etc. of infected individuals.

Assertion : Dragonflies can be used to decrease occurrence of diseases like malaria, dengue, etc. Reason : Baculoviruses are effective in controlling may insects and other arthropods.

Which of the following statements is/are not correct for single cell protein (SCP)? (i) The biomass is obtained from unicellular microorganisms only. (ii) It provides a protein rich supplement. (iii) They can be grown easily on materials like waste water from potato processing plants, straw, manure, sewage, etc. (iv) It helps to minimise environmental pollution. (v) SCP has to be processed before use.

Read the following statements regarding the various techniques used in cancer detection. (i) Cancer detection is based on biopsy and histopathological studies of the tissue, and blood and bone marrow tests for increased cell counts in case of leukaemia. (ii) In biopsy, a piece of the suspected tissue cut into thin sections is stained and examined under microscope by a pathologist. (iii) Techniques like radiography (use of X-rays), CT (computed tomography) and MRI(magnetic resonance imaging) are very useful to detect cancers of the internal organs. (iv) Computed tomography uses strong magnetic fileds and non-ionising radiations to detect physiological changes in living tissues. (v) MRI uses X-rays and ionising radiation to generate a 3-D image of the internal structure of an object. Which of the above statements are incorrect ?

An electric heater is used in a room of total wall area 137m^(2) to maintain a temperature of 20^(@)C inside it, when the outside temperature is -10^(@)C .The walls have three different layers of materials. The innermost layer is of wood of thickness 2.5cm, the middle layer is of cement of thickness 1.0cm and the outermost layer is of brick of thickness 25.0cm. Find the power of the electric heater. Assume that there is no heat loss through the floor and the celling. The thermal conductivities of wood, cement and brick are 0.125Wm^(-1)C^(-1) , 1.5Wm^(-1)C^(-1) . and 1.0Wm^(-1)C^(-1) respectively.