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In a large commercial complex, there are four ways to reach the main road. One of the paths has loose soil, the second is laid with polished marble, the third is laid with bricks and the fourth has a gravel surface. It is raining heavily and Paheli wishes to reach the main road. The path on which she is least likely to slip is (a) loose soil. (b) polished marble. (c) bricks. (d) gravel.

Answer: (d) gravel She should use a gravel surface path because only in this path. She will have sufficient friction... View Article

In an electroscope, if a negatively charged body is brought in contact with the metal clip, the strips of the electroscope diverge. If now another charged object carrying an equal amount of positive charge is brought in contact with the clip, what will happen?

Answer: If the clip of the electroscopic gets in contact with the positively charged object then negatively charged provided earlier... View Article

In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.

Answer: Because water in water hoses contains salts, it is an excellent conductor of electricity. If the area’s electrical supply... View Article

In Fig, two boys A and B are shown applying force on a block. If the block moves towards the right, which one of the following statements is correct? (a) The magnitude of force applied by A is greater than that of B. (b) The magnitude of force applied by A is smaller than that of B. (c) The net force on the block is towards A. (d) The magnitude of force applied by A is equal to that of B.

Answer: (a) Magnitude of force applied by A is greater than that of B. When force is applied to a... View Article

In Fig. mark the arrows (←), (→), (↓), or (↑) to show the direction of sunlight

Answer: The Earth’s day and night are determined by the Sun’s position. The day will be on the side of... View Article

In Fig., a boy is shown pushing the box from right to left. The force of friction will act on the box (a) from right to left (←) (b) from left to right (→) (c) vertically downwards (↓) (d) vertically upwards (↑)

Answer: (b) from left to right (→) Frictional Force When the surface of one object comes into touch with the... View Article

In order to reduce the loudness of a sound, we have to (a) decrease its frequency of vibration of the sound. (b) increase its frequency of vibration of the sound. (c) decrease its amplitude of vibration of the sound. (d) increase its amplitude of vibration of the sound.

Answer: (c) decrease its amplitude of vibration of the sound. Sound is directly proportional to the loudness of sound. As... View Article

In the circuit given as Fig. , Boojho observed that copper is deposited on the electrode connected to the negative terminal of the battery. Paheli tried to repeat the same experiment. But she could find only one copper plate. Therefore she took a carbon rod as a negative electrode. Will copper be still deposited on the carbon rod? Explain your answer.

Answer: Copper will be deposited on the carbon rod from the copper sulphate solution. When an electric current is passed... View Article

In the circuit shown in Fig., when the circuit is completed, the hammer strikes the gong. Which of the following force is responsible for the movement of the hammer? (a) gravitational force alone (b) electrostatic force alone (c) magnetic force alone (d) frictional force alone

Answer: (c) magnetic force alone When electric current passes through the coil, it acts as an electromagnet, producing magnetic force.... View Article

In the circuit shown in Fig., when the key is closed, the compass needle placed in the matchbox deflects. Name the force which causes this deflection.

Answer: When the switch is closed, current flows through the wire, creating a magnetic field surrounding the wire, which exerts... View Article

In the figure of the human eye, the cornea is represented by the letter (a) A (b) B (c) C (d) D

Answer: (c) C Cornea The human eye is triple-layered. The three layers are sclera, choroid and retina. The sclera is... View Article

In the given Fig. out of the positions A, B, C and D which will indicate the position of the sun? Draw the sun at the appropriate position.

Answer: The Sun will be in the C position. It can be identified as the illuminated side of the Earth... View Article

In the purification of copper, a thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transfered to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?

Answer: Because electric current dissociates copper and sulphate when passed through the copper sulphate solution, the thick rod of impure... View Article

In triangle ABC, right-angled at B, if tan A = 1/√3 find the value of: (i) sin A cos C + cos A sin C (ii) cos A cos C – sin A sin C

Given, in ∆ABC right angled at B, tan a= √3 Let ΔABC in which ∠B=90° tan A = BC/AB =... View Article

Is 8/9 the multiplication inverse of -1(1/8). Why or why not?

Answer: The multiplicative inverse of a number N is represented by 1/N or N-1. It is also called reciprocal, derived... View Article

Is it possible to predict the occurrence of an earthquake?

Answer: No, it is impossible to predict when an earthquake will occur. Earthquake An earthquake is the shaking of the... View Article

Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.

Answer: No, conducting electrical repairs during a heavy downpour is extremely dangerous for an electrician. Rather, it is highly dangerous... View Article

Is the distilled water acidic/basic/neutral? How would you verify it?

Answer: Distilled water is a pure type of water that does not contain any ions. It is a compound made... View Article

Is there a force of friction between the wheels of a moving train and iron rails? If yes, name the type of friction. If an air cushion can be introduced between the wheel and the rail, what effect will it have on the friction?

Answer: Yes, there is always friction between a moving train’s wheels and the iron rails. Because the wheels are rolling... View Article

It is difficult to cut cloth using a pair of scissors with blunt blades. Explain.

Answer: Cutting cloth with a pair of scissors with blunt blades is difficult since blunt blades have a larger surface... View Article

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