question_answer6) A student measured the minimum force F1 to just move a rectangular wooden block with largest surface area on a surfaceby a spring balance. Again measured the minimum force F2 to just move the block kept with smallest surface area on the table. After repeating his experiment, he established a relation between the two forces. Find this relation.View Answer play_arrow
question_answer15) Look at the diagram above and answer the following questions (a) When a force is applied through thefree end of the spring balance A, thereading on the spring balance A is15 g wt. What will be the reading of spring balance B? (b) Write reasons for your answer. (c) Name the force which balance Aexerts on balance B and the force of balance B on balance A.View Answer play_arrow
question_answer16) (a) To prepare iron sulphide, by heating a mixture of iron fillings and sulphur powder, which apparatus should be use? (b) What happens when magnet is rolledin the compound of iron sulphide?View Answer play_arrow
question_answer17) The teacher asked the students to record correctly results of the experiment done to detect the presence of metanil yellow in the adulterated arhar dal sample that was provided to them.
|A||5 g dal + 5 g metanil yellow.||Dal turns yellow.||Metanil yellow present.|
|B||5 g dal + 5 ml water + 2 drops of HCI.||Solution turns pink.||Metanil yellow present in the sample.|
|C||5 g dal + 5 ml water + pinch of metanil yellow.||Water turns yellow.||Metanil yellow present.|
|D||5 g dal + 5 ml water + 2 drops of HCI.||Metanil yellow present.||Water turns yellow and then pink.|
question_answer20) Alka's mother bought a new refrigerator which was frost free. Alka was unaware of the frost free technology of refrigerator. She wanted to know about this. So, she asked to her mother about this. (a) What are the values shown by Alka? (b) How did her mother explain suchthing?View Answer play_arrow
question_answer24) Answer the following questions (a) What is division of labour with reference to multicellular organisms? (b) Why striated muscles are also knownas skeletal muscles? (c) Which structure takes impulse a way from a neuron.View Answer play_arrow
question_answer25) Answer the following questions (a) Heart pumps blood all through the body. Can you explain the reason behind this peculiar ability of heart? (b) Animals of colder regions and fishesof cold water have thicker layer of subcutaneous fat. Why?View Answer play_arrow
question_answer27) A girl of mass 40 kg jumps with a horizontal velocity of onto a stationary cart with friction less wheels. The mass of the cart is 3 kg. What is her velocity as the cart starts moving? Assume that there is no external unbalanced force working in the horizontal direction?View Answer play_arrow
question_answer30) A car falls off a ledge and drops to the ground in 1 s. Let (for simplifying the calculation). (a) What is its speed on striking theground? (b) How high is the ledge from theground? (c) What is its average speed during the 1 s?View Answer play_arrow
question_answer31) Humans and all other animals dependon plants for their food. Hard work of several years have resulted in the development of tissue culture technology by scientists. What can be the application of such technology inour present society? Or Name the following (a) Tissue that forms the inner lining of our mouth. (b) Tissue that connects muscle to bonein humans. (c) Tissue that transport food in plants. (d) Tissue that stores fat in our body. (e) Connective tissue with a fluid matrix. (f) Tissue present in the brain.View Answer play_arrow
question_answer32) Answer the following questions (a) Farmer 'X' planted soyabean + maize+ cowpea (lobia) in the same field simultaneously in a set row pattern. Farmer 'Y' planted cereal crop in one season and leguminous plant in next season on the same piece of land inpreplanned succession. Name the cropping pattern used by the farmers'X' and 'Y'. (b) What are the advantages of different cropping patterns followed by the farmers 'X' and 'Y'? (c) Differentiate between mixed cropping and mixed farming. Or One of your family friend is thinking toopen a dairy farm for economic purpose. He wants to earn profits by selling milk. While he was discussing this with your father, what additional information can you give based on your knowledge for maintenance of catties?View Answer play_arrow
question_answer33) A 8000 kg engine pulls a train of 5 wagons, each of 2000 'kg, along ahorizontal track. If the engine exerts a force of 40000 N and the track offers a friction force of 5000 N, then calculate (a) the net acceleration force, (b) the acceleration of the train and (c) the force of wagon 1 on wagon 2. Or The driver of train A travelling at a speed ofapplies brakes and retards the train uniformly. The train stops in 5 s. Another train B is travelling on the parallel with a speed of Its driver applies the brakes and the train retards uniformly; train B stops in 10 s. Plot speed-time graphs for both the trains on the same axis. Which of the trains travelled farther after the brakes were applied?View Answer play_arrow
question_answer34) Give reasons (a) A gas fills completely the vessel in which it is kept. (b) A gas exerts pressure on the walls of the container. (c) A wooden table should be called asolid. (d) We can easily move our hand in air, but to do the same through a solid block of wood, we need a karate expert. Or (a) You want to wear your favorite shirtto a party, but the problem is that it isstill wet after a wash. What steps would you take to dry it faster? (b) It is a hot summer day, Priyanshi and Ali are wearing cotton and nylonclothes respectively. Who do you think would be more comfortable and why?View Answer play_arrow
question_answer35) Explain the following giving examples (a) Saturated solution (b) Pure substance (c) Colloid (d) Suspension Or A group of students took an old shoe box and covered it with a black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample containedin a beaker/tumbler in the box as shown in the figure. They were amazed to see that milk taken in the tumbler was illuminated. They tried the sameactivity by taking a salt solution but found that light simply passed throughit? (a) Explain why the milk sample was illuminated. Name the phenomenon involved. (b) Same results were not observed witha salt solution. Explain. (c) Can you suggest two more solutions which would show the same effect as shown by the milk solution?View Answer play_arrow
question_answer36) Derive the equations of motion for uniformly accelerated motion from velocity-time graph. Or Distance travelled by a train and time taken by it is shown in the following table. (a) Plot distance-time graph. (b) What is the average speed of the train? (c) When is the train travelling at the highest speed? (d) At what distance does the train slowdown? (e) Calculate the speed of the train between 10:40 AM to 11:00 AM.
|Time||Distance (in km)|
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