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.
(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
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.
(i) Roasting: It is the process of heating sulphide ore in the presence of excess of air to form oxide. 2MS + 3O₂ ⟶ 2MO + 2SO₂↑ Calcination: It is the Process of heating carbonate ore in the presence of limited supply of air to form oxide. MCO₃ ⟶ MO +CO₂↑ (ii) Copper can be refined by electrolytic mRead more
(i) Roasting: It is the process of heating sulphide ore in the presence of excess of air to form oxide.
2MS + 3O₂ ⟶ 2MO + 2SO₂↑
Calcination: It is the Process of heating carbonate ore in the presence of limited supply of air to form oxide.
MCO₃ ⟶ MO +CO₂↑
(ii) Copper can be refined by electrolytic method. The electrolyte is a solution of copper sulphate. Cathode is a strip of pure copper. Anode is impure copper
When we touch a hot object, how does our body mechanism protect us from getting burnt? State the role of the brain in reflex action.
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
See lessgetting 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.
State reason for the following: (i) In human heart the walls of the ventricles are thicker than the auricles. (ii) During the breathing cycle even after forceful exhalation the exchange of gases continues. (iii) In green plants during the day carbon dioxide is generated in respiration but is not released out.
(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
See lesspressure 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
Give one most suitable word {or the following statements: (i) Metal oxides which show basic as well as acidic behaviour. (ii) Some metals produce a sound on striking a hard surface.8
(i) Amphoteric oxides (ii) Sonorous (iii) Lustrous.
(i) Amphoteric oxides
See less(ii) Sonorous
(iii) Lustrous.
When we overeat we feel burning sensation in the stomach. State reason. Which substance can be used to nullify its effect? Give one example, state the property due to which we feel relief.
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.
See lessFor example, sodium bicarbonate acts as antacid by reacting with excess acid and increasing the pH i.e., adding an alkali.
(i) Differentiate between calcination and roasting. (ii) Suggest a method of refining of copper.
(i) Roasting: It is the process of heating sulphide ore in the presence of excess of air to form oxide. 2MS + 3O₂ ⟶ 2MO + 2SO₂↑ Calcination: It is the Process of heating carbonate ore in the presence of limited supply of air to form oxide. MCO₃ ⟶ MO +CO₂↑ (ii) Copper can be refined by electrolytic mRead more
(i) Roasting: It is the process of heating sulphide ore in the presence of excess of air to form oxide.
See less2MS + 3O₂ ⟶ 2MO + 2SO₂↑
Calcination: It is the Process of heating carbonate ore in the presence of limited supply of air to form oxide.
MCO₃ ⟶ MO +CO₂↑
(ii) Copper can be refined by electrolytic method. The electrolyte is a solution of copper sulphate. Cathode is a strip of pure copper. Anode is impure copper