In a car battery, plates of lead and lead dioxide are immersed in a liquid L. A chemical reaction occurs leading to the production of lead sulphate and water. The solution L is likely to be a/an [blank_start]Base.[blank_end]
Observe the food chain given below and choose the right option.
Petroleum and natural gas are found in layers deep within the surface of the earth. They are formed when layers of [blank_start]organic[blank_end] matter are subjected to intense heat and pressure. Natural gas requires [blank_start]higher[blank_end] amounts of heat and pressure to form than petroleum.
After a harvest ,the fields are sometimes burned to clear them in preparation for the next season.
Choose any two statements which show the importance of doing this.
helping in the removal of plant matter
making the soil softer and aerating it
reducing the carry-over of certain pests
preventing loss of soil by the action of wind
If we dip one end of a pencil or some other object into water at an angle to the surface, the submerged part looks [blank_start]bent[blank_end]. Its image is displaced because the light coming from the underwater portion of the object changes [blank_start]direction[blank_end] at it leaves the water. This bending of light as it passed from one transparent medium into another is called [blank_start]refraction[blank_end].
Refraction of light is caused by the difference in [blank_start]speed[blank_end] of light in different media.