class 7 - Science - Ch1 - Nutrition in Plants

Nutrition in Plants

Q1: Why do organisms need to take food?

Answer: All organisms take food and utilise it to get energy for the growth and maintenance of their bodies.

Q2: Why do plants use the nitrogen present in soil? How is this nitrogen replenished in the soil?

Answer: Plants cannot absorb nitrogen in gas form; they need it in soluble form. Therefore, they use the nitrogen present in soil to prepare proteins.

Atmospheric nitrogen is fixed in soil by nitrogen-fixing bacteria such as Rhizobium,which live in the root nodules of leguminous plants such as gram, peas, beans, etc. In return, the plants provide food and shelter to the bacteria.

Explore Biodigital Human Body in 3D

The website BioDigitalHuman provides interactive 3D Human body and anatomical systems views.

To view the website you need a browser supports HTML5 and WebGL. Chrome supports these. I think you need to install plugins in Firefox and IE9+. You need a broadband connection to view the site. No doubt it has been the award winning site.

NTSE (SAT Quiz-3)

Q1: Which of the following is an antibiotic?
       a. Aspirin
       b. Penicillin
       c. Paracetamol
       d. Sulphadizine

Q2: Digestion of food starts in:
       a. mouth
       b. liver
       c. stomach
       d. intestines

Q3: By taking the pulse rate of the human body, a doctor determines
       a. heartbeat
       b. functioning of heart valves
       c. condition of lever
       d. functioning of lungs

Q4: A thermostat is used to
       a. purify air
       b. regulate humidity
       c. regulate temperature
       d. regulate air pressure

Q5: Heat from the sun reaches the earth by
        a. reflection
        b. conduction
        c. convection
        d. radiation

Q6: Dew forms most readily on nights that are:
        a. calm and clear
        b. stormy
        c. windy
        d. cloudy

Q7: The full moon rises in the
        a. east
        b. west
        c. south
        d. north

Q8: An aeroplane is able to fly because
       a. it is lighter than air
       b. it is heavier than air
       c. it is made up of very light material
       d. moving air can lift objects

Q9: The souring of milk is caused by the action of
        a. protozoan
        b. bacteria
        c. virus
        d. fungus

Q10. The smallest thing that can cause disease in the human body is
         a. flea
         b. bacteria
         c. protozoa
         d. virus

Q11: The most abundant gas in the air is:
         a. oxygen
         b. carbon dioxide
         c. nitrogen
         d. hydrogen

Q12: Which element is common between brass and bronze
         a. copper
         b. Iron
         c. Zinc
         d. Aluminium

Q13: The densest element known so far is
         a. gold
         b. mercury
         c. osmium
         d. tungsten

Q14: The most ductile element is
         a. gold
         b. silver
         c. iron
         d. aluminium

Q15: The metal having the highest melting point is
         a. chromium
         b. tungsten
         c. diamond
         d. Silver

Answers: 1-b     2-a     3-a     4-c    5-d     6-a     7-a    8-d    9-b    10-d

                11-c    12-a   13-c    14-a   15-b

See other quizes at link1, link2, link3

CBSE Class 7 - Science - Light - Questions & Answers

Class 7 - Ch 15 - Science - Light - Questions & Answers

Question1: Fill in the blanks
a. An image that cannot be obtained on a screen is called ______.

b. Image formed by a convex _______ is always virtual and smaller in size.

c. An image formed by a __________ mirror is always of the same size as that of the object.

d. An image which can be obtained on a screen is called a _________ image.

e. An image formed by a concave ___________ cannot be obtained on a screen.

Answers:
1 a) virtual image
b) convex mirror
c) plane
d) real
e) concave lens 

Question2: Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) We can obtain an enlarged and erect image by a convex mirror. (T/F)
(b) A concave lens always form a virtual image. (T/F)
(c) We can obtain a real, enlarged and inverted image by a concave mirror. (T/F)
(d) A real image cannot be obtained on a screen. (T/F)
(e) A concave mirror always form a real image. (T/F)

Answers: a-false b-true c-true d-false e-false

Class 7 - Science Chapter 15 - Light

 Class 7 - Science Chapter 15 - Light

1. Light travels along straight lines. This property is called rectilinear propagation of light.

2. Any polished or a shining surface acts as a mirror.

3. Change in direction of light from an object is called reflection of light.

4. An image which can be obtained on a screen is called a real image.

5. An image which cannot be obtained on a screen is called a virtual image.

6. The image formed by a plane mirror is erect. It is virtual and is of the same size as the object. The image is at the same distance behind the mirror as the object is in front of it.

7. In an image formed by a mirror, the left side of the object is seen on the right side in the image, and right side of the object appears to be on the left side in the image. This property is called Lateral Inversion.