MODEL PAPER 8 Science - MODEL PAPER 8

Assertion (A): Ecology is study of relationship between living organisms and their environment.
Reason (R): The biotic community and non-living environment of an area function together to form an ecosystem.

Assertion (A): Force experienced by moving charge will be maximum if direction of velocity of charge is perpendicular to applied magnetic field.
Reason (R): Force on moving charge is independent of direction of the applied magnetic field.

Assertion (A): Asexual reproduction is a primitive type of reproduction.
Reason (R): Asexual reproduction involves only mitotic cell division.

Assertion (A): Sodium metal is stored under Kerosene.
Reason (R): Metallic sodium melts when exposed to air

In the following groups of materials, which group contains only non-biodegradable materials?

Assertion (A): Sodium metal is stored under Kerosene.
Reason (R): Metallic sodium melts when exposed to air

Assertion (A): Asexual reproduction is a primitive type of reproduction.
Reason (R): Asexual reproduction involves only mitotic cell division.

Assertion (A): Force experienced by moving charge will be maximum if direction of velocity of charge is perpendicular to applied magnetic field.
Reason (R): Force on moving charge is independent of direction of the applied magnetic field.

Assertion (A): Ecology is study of relationship between living organisms and their environment.
Reason (R): The biotic community and non-living environment of an area function together to form an ecosystem.

List two main causes of a person developing near sightedness. Show with the help of a ray diagram how this defect can be corrected.

Complete the below diagram by filling spaces marked as A, B, C and D:

If the image formed by a lens for all positions of an object placed in front of it is always erect and diminished, what is the nature of this lens? Draw a ray diagram to justify your answer.

Explain the role of liver in excretion.

The refractive indices 1.0003, 1.31 1.5 respectively of Air, Ice and Benzine in which of these does the light travels fastest?

Explain Mendel's observation when he crossed a homozygous tall (TT) plant with homozygous dwarf (tt) plant followed by self-cross.

i. Why is nutrition a necessity for an organism? State three reasons.
ii. What is likely to happen if green plants disappear from Earth?

Why do we call pituitary gland as the master gland? Where is it located and what are its functions?

With the help of suitable diagrams explain the various steps of budding in Hydra.

Define structural isomer and draw the isomeric structures of butane. Compare the structure of benzene and cyclohexane by drawing them.

An insulated copper wire wound on a cylindrical cardboard tube such that its length is greater than its diameter is called a solenoid. When an electric current is passed through the solenoid, it produces a magnetic field around it. The magnetic field produced by a current-carrying solenoid is similar to the magnetic field produced by a bar magnet. The field lines inside the solenoid are in the form of parallel straight lines. The strong magnetic field produced inside a current-carrying solenoid can be used to magnetize a piece of a magnetic material like soft iron when placed inside the solenoid. The strength of the magnetic field produced by a current-carrying solenoid is directly proportional to the number of turns and strength of the current in the solenoid.


(a) What would be the strength of the magnetic field inside a long current-carrying straight solenoid?
(b) Which end is north and which end is south pole when current flows through a solenoid?
(c) A long solenoid carrying a current produces a magnetic field B along its axis. If the current is double and
the number of turns per cm is halved, then what will be the new value of the magnetic field?

OR

A soft iron bar is enclosed by a coil of insulated copper wire as shown in the figure. When the plug of the
key is closed, then where would the face B of the iron bar be marked?

Following questions are based on the two tables given below. Study these tables related to blood sugar levels:
Table A (Blood glucose chart)

	Mean Blood Glucose Level (mg/dL)
Doctor's advice needed	380
	350
	315
	280
	250
	215
Good	180
	150
Excellent	115
	80
	50

Table B (Blood Report of Patient X and Y)

Time of check	Blood Glucose ranges (mg/dL)
	Patient X	Patient Y
Before breakfast (Fasting)	<100	70 – 130
Before lunch, supper and snack	<110	70 - 130
Two hours after meals	<140	<180
Bedtime	<120	90 - 15

(a). Refer to Table B showing the blood report of the levels of glucose of patients X and Y. Infer the disease
which can be diagnosed from the given data.
(b). Identify the hormone whose level in the blood is responsible for the above disease.
(c). High/low sugar and a low/high-fat diet What would you recommend to the affected patient?

OR

Refer to Table A and suggest the value of the mean blood glucose level beyond which doctor’s advice is necessary.

Salt of a strong acid and strong base is neutral with a pH value of 7. NaCl common salt is formed by a combination of hydrochloride and sodium hydroxide solution. This is the salt that is used in food. Some salt is called rock salt, bed of rock salt was formed when seas of bygone ages dried up. The common salt thus obtained is an important raw material for various materials of daily use, such as sodium hydroxide, baking soda, washing soda, and bleaching powder.
a. If given acids are phosphoric acid, carbonic acid, hydrochloric acid and sulphuric acid, then which acid
does not form an acidic salt?
b. What is the formula of baking soda?

OR

Name the substance which on treatment with chlorine to obtain bleaching powder