Choose the correct alternative and answer the following from the options given: 1. If Rani stands 2m away in front of a plane mirror, then she moves towards the mirror by 20 cm, h... Choose the correct alternative and answer the following from the options given: 1. If Rani stands 2m away in front of a plane mirror, then she moves towards the mirror by 20 cm, how far from her will her image now be located? (a) 2.2 m (b) 3.6 m (c) 4.4 m (d) 1.8 m 2. Which of the following represents pressure? (a) kgms^{-1} (b) kgms^{-2} (c) kgm^{-1}s^{-1} (d) kgm^{-1}s^{-2} 3. An object is placed symmetrically between two mirrors inclined at 30° to each other. How many images will you see? (a) 13 (b) 12 (c) 11 (d) 10 4. Which of the following statements is/are true: P - Heat always flows from a body with more heat to a body with less heat Q - If two hot liquids are mixed, their temperature gets added up. R - The density of water decreases on cooling from 4°C to 0°C (a) Only R (b) Only P (c) P & R (d) Q & R 5. Which of the following is a correct set of green-house gases? (a) CO2, SO2, N2 (b) O3, CFCs, CH4 (c) CO2, CH4, CFCs (d) NO2, SO2, CO2 6. Which of the following is true for negative zero error: (a) Zero of the main scale is to the right of zero of Vernier scale (b) It shows a reading higher than the actual reading (c) Both (a) and (b) (d) Neither (a) nor (b) 7. If water is used in a simple barometer, the height of the water column would be approximately: (a) 10 cm , (b) 100 cm, (c) 1000 cm, (d) 10000 cm 8. The clock in Shreya's bedroom has marks instead of numbers on its dial. The clock appears to indicate 4:35 pm when Shreya looks at it through a plane mirror. What is the actual time? (a) 8:20 (b) 8:25 (c) 7:25 (d) 7:20 9. Identify the odd one out: (a) amperes (b) joules (c) newtons (d) pascals
Understand the Problem
The image contains a set of multiple-choice questions from a physics exam for ICSE Class VIII. The questions cover various topics, including reflection, pressure, heat transfer, greenhouse gases, measurement errors, barometers, time in mirrors, and identifying units. We need to categorize these questions and extract the text.
Answer
The answers are: 1. (b) 3.6 m 2. (d) kgm^{-1}s^{-2} 3. (c) 11 4. (c) P & R 5. (c) CO2, CH4, CFCs 6. (a) Zero of the main scale is to the right of zero of Vernier scale 7. (d) 10000 cm 8. (a) 8:20 9. (a) amperes
- (b) 3.6 m
- (d) kgm^{-1}s^{-2}
- (c) 11
- (c) P & R
- (c) CO2, CH4, CFCs
- (a) Zero of the main scale is to the right of zero of Vernier scale
- (d) 10000 cm
- (a) 8:20
- (a) amperes
Answer for screen readers
- (b) 3.6 m
- (d) kgm^{-1}s^{-2}
- (c) 11
- (c) P & R
- (c) CO2, CH4, CFCs
- (a) Zero of the main scale is to the right of zero of Vernier scale
- (d) 10000 cm
- (a) 8:20
- (a) amperes
More Information
Here's how to arrive at some of the answers:
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Rani is initially 2m from the mirror. She moves 20cm (0.2m) closer, so she is now 1.8m from the mirror. Her image is also 1.8m behind the mirror. The distance between Rani and her image is 1.8m + 1.8m = 3.6m.
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Pressure is Force/Area. Force = mass x acceleration (kg x m/s^2). Area = m^2. So Pressure = (kg x m/s^2) / m^2 = kg / (m x s^2) = kgm^{-1}s^{-2}
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Number of images = (360/angle) - 1 = (360/30) - 1 = 12 - 1 = 11 images.
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The height of water in a barometer is given by (h = \frac{P}{\rho g}), where (P) is the atmospheric pressure, (\rho) is the density of water, and (g) is the acceleration due to gravity. Since water is much less dense than mercury (the fluid typically used in barometers), the height of the water column will be much greater. Standard atmospheric pressure can support approximately 0.76 meters of mercury, but it would support about 10.3 meters of water, or 1030 cm. So the closest answer provided is (d) 10000 cm.
Tips
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