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Which of the following precautions need not be taken while using electric gadgets/appliances/circuit? (a) We should never touch a lighted electric bulb connected to the mains. (b) We should never experiment with the electric supply from the mains or a generator or an inverter. (c) We should never use just any wire or strip of metal in place of a fuse. (d) We should never turn the switch in ON position.

Answer: (d) We should never turn the switch in ON position. To use electric gadgets/appliances/circuit switch should be turned on The switch... View Article

When a switch is in OFF position, (i) circuit starting from the positive terminal of the cell stops at the switch. (ii) the circuit is open. (iii) no current flows through it. (iv) current flows after some time. Choose the combination of the correct answer from the following. (a) all are correct (b) (ii) and (iii) are correct (c) only (iv) is correct (d) only (i) and (ii) are correct

Answer: (b) (ii) and (iii) are correct When the switch is off, the circuit will be incomplete hence it is open and no current flows through it.... View Article

Choose the statement which is not correct in the case of an electric fuse. (a) Fuses are inserted in electric circuits of all buildings. (b) There is a maximum limit on the current which can safely flow through the electric circuits. (c) There is a minimum limit on the current which can safely flow in the electric circuits. (d) If a proper fuse is inserted in a circuit it will blow off if current exceeds the safe limit.

Answer: (c) There is a minimum limit on the current which can safely flow in the electric circuits. In case of electric fuse, there is only a... View Article

Boojho goes to the football ground to play football. The distance-time graph of his journey from his home to the ground is given in the Figure (a) What does the graph between point B and C indicate about the motion of Boojho? (b) Is the motion between 0 to 4 minutes uniform or nonuniform? (c) What is his speed between 8 and 12 minutes of his journey?

Answer: (a) As time changes, the graph between points B and C is parallel to the x-axis, indicating that there is no motion. Boojho is in a rest... View Article

Distance between Bholu’s and Golu’s house is 9 km. Bholu has to attend Golu’s birthday party at 7 o’clock. He started from his home at 6 o’clock on his bicycle and covered a distance of 6 km in 40 minutes. At that point, he met Chintu and he spoke to him for 5 minutes and reached Golu’s birthday party at 7 o’clock. With what speed did he cover the second part of the journey? Calculate his average speed for the entire journey. The speed with which Bholu covered the second part of the journey

Answer: The speed with which Bholu covered the second part of the journey = Distance left to reach Golu's house/ Time left = (9 km - 6km)/(1 hour... View Article