MODEL PAPER 5 Science - MODEL PAPER 5

Assertion (A): An ecosystem consists of biotic components and abiotic components.
Reason (R): Biotic and abiotic components play important roles for the sustenance of life and work independently in all ecosystems.

Assertion (A): For a point on the axis of a circular coil carrying current, magnetic field is maximum at the centre of the coil.
Reason (R): Magnetic field is proportional to the distance of point from the circular coil.

Assertion (A): Urethra in human males acts as a urinogenital canal.
Reason (R): Urethra carries only urine while sperms are carried by vasa deferentia only.

Assertion (A): A chemical reaction becomes faster at higher temperatures.
Reason (R): At higher temperatures, molecular motion becomes more rapid.

Which group(s) of organisms is/are not a constituent of a food chain?
A. Grass, lion, rabbit, wolf
B. Plankton, man, fish, grasshopper
C. Wolf, grass, snake, tiger
D. Frog, snake, eagle, grass, grasshopper

Assertion (A): A chemical reaction becomes faster at higher temperatures.
Reason (R): At higher temperatures, molecular motion becomes more rapid.

Assertion (A): Urethra in human males acts as a urinogenital canal.
Reason (R): Urethra carries only urine while sperms are carried by vasa deferentia only.

Assertion (A): For a point on the axis of a circular coil carrying current, magnetic field is maximum at the centre of the coil.
Reason (R): Magnetic field is proportional to the distance of point from the circular coil.

Assertion (A): An ecosystem consists of biotic components and abiotic components.
Reason (R): Biotic and abiotic components play important roles for the sustenance of life and work independently in all ecosystems.

How is ozone formed in the upper atmosphere? State its importance. What is responsible for its depletion? Write one harmful effect of ozone depletion.

Which chemical is used in fire extinguishers. It is harmful as it leads to depletion of ozone layer, thus allowing UV radiations from the Sun to enter into the atmosphere.

State laws of refraction of light.

How does aerobic respiration differ from anaerobic respiration?

Find out the following in the electric circuit given in Figure

i. The potential difference across 4Ω resistance
ii. The power dissipated in 4Ω resistor

An object is kept at a distance of 18 cm, 20 cm and 30 cm, from a lens of power+5D. (i) In which case or cases would you get a magnified image? (ii) Which of the magnified image can we get on a screen? (b) List two widely used applications of a convex lens.

In a pea plant, find the contrasting trait if
i. the position of flower is terminal
ii. the flower is white in colour
iii. shape of pod is constricted

Explain nutrition in Amoeba.

Discuss the important characteristics of covalent compounds.

Given below is a diagram of the human endocrine system.

Using the given diagram, answer the following questions:
i. How pituitary gland regulates the growth of the body?
ii. Which hormone is responsible for the carbohydrate, protein, and fat metabolism in the body?
iii. Which pair of glands prepare the body to deal with emergency situations?
iv. Which gland secretes insulin and what does it do in the body?
v. What is the function of endocrine glands?

How are the images formed when an object is moved from infinity to the convex lens?

Explain various steps of budding in yeast.

A student fixes a sheet of white paper on a drawing board using some adhesive materials. She places a bar magnet in the centre of it and sprinkles some iron filings uniformly around the bar magnet using a salt sprinkler. On tapping the board gently, she observes that the iron filings have arranged themselves in a particular pattern.
(a) What makes iron filings arrange in a definite pattern?
(b) Draw a diagram to show this pattern of iron filings.
(c) How is the direction of magnetic field at a point determined using the field lines? Why do two magnetic field lines not cross each other?
OR
How are the magnetic field lines of a bar magnet drawn using a small compass needle? Draw one magnetic field line each on both sides of the magnet.

In animals, control and coordination are provided by nervous and muscular tissues. Touching a hot object is an urgent and dangerous situation for us. We need to detect it and respond to it. How do we detect that we are touching a hot object? All information from our environment is detected by the specialised tips of some nerve cells. These receptors are usually located in our sense organs, such as the inner ear, the nose, the tongue, and so on. So gustatory receptors will detect taste while olfactory receptors will detect the smell. This information, acquired at the end of the dendritic tip of a nerve cell, see figure, sets off a chemical reaction that creates an electrical impulse. This impulse travels from the dendrite to the cell body, and then along the axon to its end.

(a) Name the largest cell present in the body.
(b) What is an axon?
(c) Name one gustatory receptor and one olfactory receptor present in a human beingsettings
OR
Name the following parts of a neuron:
a. Where information is acquired.
b. Through which information travels as an electrical impulse.

The teacher while conducting practicals in the laboratory divided the students into three groups and gave them various solutions to find out their pH and classify them into acidic, basic and neutral solutions.
Group A - Lemon juice, vinegar, colourless aerated drink
Group B - Tomato juice, coffee, ginger juice
Group C - Sodium hydroxide, sodium chloride, lime water
(a) For the solutions provided, which group is/are likely to have pH value (i) less than 7, and (ii) greater than 7?
(b) List two ways of determining pH of a solution.
OR
Explain, why the sour substances such as lemon juice are effective in cleaning the tarnished copper vessels.