1. (a) The right hand thumb rule helps to determine the direction of magnetic field of straight current carrying conductor. According to this rule, hold the current carrying wire in your right hand such that the thumb is sketched along the direction of current. Then, the fingers will wrap around the wiRead more

    (a) The right hand thumb rule helps to determine the direction of magnetic field of straight current carrying conductor. According to this rule, hold the current carrying wire in your right hand such that the thumb is sketched along the direction of current. Then, the fingers will wrap around the wire in the direction of the magnetic field.
    (b) Fleming’s right hand rule is used to determine the direction of induced current in a conductor. It states that hold the forefinger, the central finger and the thumb of the right hand mutually perpendicular to each other such that the forefinger indicates the direction of magnetic field and the thumb is in the direction of motion of conductor. Then, the central finger shows the direction of current induced in the conductor.

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  2. When we touch a hot object; the body mechanism is such that it protects us from getting burnt. Hence, rather than to think about it, detects the heat and responds quickly. Reflex arc is such a connection that carries information about a stimulus through sensory nerves, to central nervous system/ i.eRead more

    When we touch a hot object; the body mechanism is such that it protects us from
    getting burnt. Hence, rather than to think about it, detects the heat and responds quickly. Reflex arc is such a connection that carries information about a stimulus through sensory nerves, to central nervous system/ i.e., spinal cord, which processes the information, sends message through another set of nerves, motor nerves, to the motor area (like muscle) to withdraw, thereby preventing us from any harm. Reflex arc are formed in the spinal cord itself although the information also goes on to reach brain where the encounter remains in the memory and make us a\ rare of our action. Secondly there are certain reflex actions under the control of brain known as cerebral reflex. Closure of eyes exposed to flash of light, salvation at sight or smell of food, peristalsis, inspiration and expiration are few examples of cerebral reflexes.

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  3. (i) In human heart ventricles have to pump blood to distant body parts, hence the pressure is much higher, as compared to auricles which pump blood to closer lungs. Hence, walls of ventricles are thicker. (ii) During breathing, even after forceful exhalation, gaseous exchange continues. This is becaRead more

    (i) In human heart ventricles have to pump blood to distant body parts, hence the
    pressure is much higher, as compared to auricles which pump blood to closer lungs. Hence, walls of ventricles are thicker.
    (ii) During breathing, even after forceful exhalation, gaseous exchange continues. This is because small amount of air still remains in our lungs and hence diffusion continues.
    (iii) In green plants during the day carbon dioxide is generated in respiration, but is not released out, as this carbon dioxide is used to make glucose during photosyntheesis

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  4. When we overeat, the burning sensation in the stomach is due to excess secretion of acid. An antacid can be used to nullify the effect of excess acid. For example, sodium bicarbonate acts as antacid by reacting with excess acid and increasing the pH i.e., adding an alkali.

    When we overeat, the burning sensation in the stomach is due to excess secretion of acid. An antacid can be used to nullify the effect of excess acid.
    For example, sodium bicarbonate acts as antacid by reacting with excess acid and increasing the pH i.e., adding an alkali.

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