Please select a subject first
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Match the important chemicals given in Column (A) with the chemical formulae given in Column (B)
| Column (A) | Column (B) |
| (a) Plaster of Paris | Ca(OH)2 |
| (b) Gypsum | CaSO4. 1/2 H2O |
| (c) Bleaching Powder | CaSO4.2H7O |
| (d) Slaked Lime | CaOCl2 |
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Which of the following statement is correct?
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Draw ray diagram showing myopic eye.
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A student sitting at the back of the classroom cannot read clearly the letters written on the blackboard. What advice will a doctor give to her? Draw ray diagram for the correction of this defect.
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A person needs a lens of power –4.5 D for correction of her vision.
- What kind of defect in vision is she suffering from?
- What is the focal length of the corrective lens?
- What is the nature of the corrective lens?
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When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?
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A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1, R2 and R3 respectively. Which of the following is true?

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State Ohm’s law? How can it be verified experimentally? Does it hold good under all conditions? Comment.
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Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the
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Calculate the total resistance of the circuit and find the total current in the circuit.
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These consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Silver bromide decomposition is used in black and white photography.
Reason: Light provides energy for this exothermic reaction.
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- Identify the gasses evolved at the anode and cathode in the above experimental set up.
- Name the process that occurs. Why is it called so?
- Illustrate the reaction of the process with the help of a chemical equation.
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State Ohm's Law. Represent it mathematically.
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What is the resistance of a conductor through which a current of 0.5 A flows when a potential difference of 2V is applied across its ends?
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Draw a diagram showing flow of energy from solar input to a food chain having four trophic levels in an ecosystem. List two inference that can be drawn from the energy flow diagram.
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You are provided with a resistor, a key, an ammeter, a voltmeter, four cells of 1.5 V each and few connecting wires. Using circuit components, draw a labelled circuit diagram to show the setup to study Ohm's law.
State the relationship between potential difference (V) across the resistor and the current (I) flowing through it. Also draw V-I graph, taking V on the X-axis.
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Study the given figure of a Food web and identify the primary consumer in the food web:

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Let the resistance of an electrical device remain constant, while the potential difference across its two ends decreases to one fourth of its initial value. What change will occur in the current through it? State the law which helps us in solving the above stated question.
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State reasons for Myopia. With the help of ray diagrams, show the:
- image formation by a myopic eye, and
- correction of myopia using an appropriate lens.
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What is meant by resistance of a conductor ? Define its SI unit.
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