Q1
mcq
1 mark
The device used to produce electricity is
- A. Galvanometer
- B. Electric generator
- C. Ammeter
- D. Electric motor.
Correct Answer: B —
Solution
An electric generator is a device that converts mechanical energy into electrical energy. A galvanometer detects current, an ammeter measures current, and an electric motor converts electrical energy into mechanical energy.
Q2
mcq
1 mark
The correct formula that shows the relationship between potential difference, electric current and resistance in an electric circuit is
- A. $I = \frac{V}{R}$
- B. $I = VR$
- C. $V = \frac{R}{I}$
- D. $R = \frac{I}{V}$
Correct Answer: A —
Solution
According to Ohm's Law, $V = IR$, where $V$ is potential difference, $I$ is current, and $R$ is resistance. Rearranging this formula for $I$ gives $I = \frac{V}{R}$. Thus, option A is the correct relationship.
Q3
mcq
1 mark
In Fleming’s right hand rule, the middle finger indicates the direction of
- A. induced electric current
- B. magnetic field
- C. motion of the conductor
- D. mechanical force.
Correct Answer: A —
Solution
According to Fleming's right-hand rule, the thumb indicates the direction of motion of the conductor, the forefinger indicates the direction of the magnetic field, and the middle finger indicates the direction of the induced electric current.
Q4
mcq
1 mark
To get diminished and real image of an object from a convex lens, the object should be placed
- A. at principal focus $F_1$
- B. between principal focus $F_1$ and $2F_1$
- C. beyond $2F_1$
- D. between principal focus $F_1$ and optical centre O.
Correct Answer: C —
Solution
For a convex lens, when an object is placed beyond $2F_1$, the image formed is real, inverted, and diminished, and it is formed between $F_2$ and $2F_2$.
Q5
short answer
1 mark
Magnetic field lines do not intersect each other. Why ?
Solution
Magnetic field lines do not intersect each other because if they did, there would be two directions of the magnetic field at the point of intersection, which is physically impossible.
Q6
short answer
1 mark
Mention the SI unit of power of lens.
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Q7
short answer
2 marks
Draw the schematic diagram of an electric circuit comprising of electric cell, electric bulb, ammeter and plug key.
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Q8
short answer
2 marks
An object is placed at 25 cm in front of a concave mirror of focal length 15 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? OR A concave lens has focal length of 15 cm. At what distance should the object from the lens be placed so that it forms an image at 10 cm from the lens?
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Q9
long answer
3 marks
Which is the major component of biogas ? Write four characteristics of a good source of energy. OR Which element is used in making solar cell ? Write any four advantages of solar cells.
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Q10
long answer
3 marks
Draw the ray diagram to show the image formation by a convex lens, when the object is kept at $2F_1$ of the lens. With the help of the ray diagram mention the position and nature of the image formed. [$F_1$ : Principal focus of the lens]
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Q11
long answer
3 marks
What are the functions of an earth wire ? It is necessary to connect the electric appliances having metallic body to the earth wire in domestic electric circuit. Why ? Explain. OR Explain Faraday’s experiment related to electromagnetic induction. Mention the difference between direct and alternate current.
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Q11
short answer
What are the functions of an earth wire ? It is necessary to connect the electric appliances having metallic body to the earth wire in domestic electric circuit. Why ? Explain.
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Q12
long answer
4 marks
a) What are the advantages of connecting electrical devices in parallel in an electric circuit instead of connecting them in series? b) How are ammeter and voltmeter connected in an electric circuit? What are their function?
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Q13
long answer
5 marks
a) What is refraction of light? State two laws of refraction of light. b) What is refractive index of light? “The refractive index of diamond is 2·42.” What is the meaning of this statement?
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Q14
mcq
1 mark
The gas liberated at the cathode in the electrolysis of water is
- A. Oxygen
- B. Hydrogen
- C. Chlorine
- D. Nitrogen.
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Q15
mcq
1 mark
Atomic number of chlorine is 17. The period number of this element in modern periodic table is
- A. 2
- B. 7
- C. 4
- D. 3.
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Q17
short answer
Explain Faraday’s experiment related to electromagnetic induction. Mention the difference between direct and alternate current.
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Q17
short answer
1 mark
Write any two uses of Plaster of Paris.
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Q18
short answer
What are the advantages of connecting electrical devices in parallel in an electric circuit instead of connecting them in series ?
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Q18
short answer
1 mark
Write the structural formula of ethene molecule.
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Q19
short answer
How are ammeter and voltmeter connected in an electric circuit ? What are their function ?
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Q19
short answer
1 mark
ZnO + C → Zn + CO. In this reaction name the reactant i) that is oxidised and ii) that is reduced.
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Q20
short answer
What is refraction of light ? State two laws of refraction of light.
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Q20
short answer
2 marks
The pH values of A, B and C solutions are 5, 6 and 7 respectively. Which of these solutions is more acidic in nature ? Why ?
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Q21
short answer
What is refractive index of light ? “The refractive index of diamond is 2·42.” What is the meaning of this statement ?
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Q21
short answer
2 marks
Draw the diagram to show the arrangement of the apparatus used for testing the conductivity of salt solution and label ‘graphite rod’.
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Q23
short answer
3 marks
What is atomic size ? In the modern periodic table the atomic size decreases along a ‘period’ and increases down the ‘group’. Why ? Explain.
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Q24
short answer
3 marks
Draw the diagram of arrangement of the apparatus to show the reaction of zinc granules with dilute sulphuric acid and testing hydrogen gas by burning. Label the following parts: i) Zinc granules ii) Delivery tube.
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Q25
short answer
3 marks
Write the balanced chemical equation for the following chemical reactions : i) Calcium carbonate $\xrightarrow{\text{Heat}}$ Calcium oxide + Carbon dioxide ii) Hydrogen + Chlorine $\rightarrow$ Hydrogen chloride iii) Magnesium + Hydrochloric acid $\rightarrow$ Magnesium chloride + Hydrogen.
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Q27
mcq
1 mark
Atmospheric layer that absorbs ultraviolet radiations coming from the sunlight is made up of this molecule.
- A. $N_2$
- B. $H_2$
- C. $O_3$
- D. $O_2$.
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Q28
short answer
2 marks
Give reason: a) Metals are used in making cooking vessels. b) Sodium metal is stored in kerosene.
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Q28
mcq
1 mark
In humans, sexually transmitted viral infection is
- A. AIDS
- B. Syphilis
- C. Tuberculosis
- D. Gonorrhoea.
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Q29
short answer
2 marks
Give reason: a) When a calcium metal reacts with water, the liberated hydrogen gas does not catch fire. b) Ionic compounds have high melting and boiling points.
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Q29
short answer
1 mark
What is the role of decomposers in an ecosystem ?
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Q30
short answer
1 mark
In males, testes are located outside the abdominal cavity in scrotum. Why ?
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Q31
short answer
2 marks
Mention the function of the following plant hormones : i) Auxin ii) Cytokinin.
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Q32
short answer
2 marks
Draw the diagram showing the longitudinal section of a flower and label ‘ovary’.
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Q33
short answer
3 marks
Which type of chemical reaction takes place when an iron nail is dipped in copper sulphate solution ? Why ? Write a balanced chemical equation for this chemical reaction.
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Q33
short answer
2 marks
Give reason : a) ‘Ventricles of the human heart have thick wall.’ b) ‘It is necessary to separate oxygenated and deoxygenated blood in mammals and birds.’
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Q34
short answer
4 marks
What are structural isomers ? Write the molecular and structural formula of butane.
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Q34
long answer
3 marks
When a tall (TT) pea plant is crossed with a dwarf (tt) pea plant, represent the result obtained in $F_2$ generation of monohybrid cross with the help of checker board and mention the ratio of varieties of plants.
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Q35
short answer
4 marks
What is catenation ? Write general formula for alkenes.
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Q35
long answer
3 marks
What is trophic level ? Flow of energy in an ecosystem is always unidirectional. Why ? Explain.
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Q36
long answer
3 marks
a) Mention any four main factors that lead to the rise of new species.
b) The experiences of an individual acquired during its lifetime cannot be passed on to its progeny. Give reason.
OR
What are fossils ? Mention the methods of estimation of dating fossils and explain briefly.
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Q37
long answer
4 marks
Which molecule is formed during the first step of cellular respiration by the breakdown of glucose molecule in cytoplasm ? Mention the types of respiration and write any two differences between them.
OR
Which are the factors essential for photosynthesis ? Mention the events that occur during this process and represent this process by balanced chemical equation.
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Q38
long answer
4 marks
Draw the diagram showing the structure of the human brain and label the following parts :
i) Cerebrum
ii) Cerebellum.
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