551: Solution of washing soda in water is:
(a) Acidic
(b) Basic
(c) Neutral
(d) Sour
552: Standard 18-carat gold sold in the market contains:
(a) 82 parts gold and 18 parts other metals
(b) 18 parts gold and 82 parts other metals
(c) 18 parts gold and 6 parts other metals
(d) 9 parts gold and 15 parts other metals
Explanation:
Standard 18-carat gold contains 18 parts gold and 6 parts other metals.
553: The terms Event Horizon, Singularity, 'String Theory and Standard Model are sometimes seen in the news in the context of
(a) Observation and understanding of the Universe
(b) Study of the solar and the lunar eclipses
(c) Placing satellites in the orbit of the Earth
(d) Origin and evolution of living organisms on the Earth
554: Acid rain is caused by pollution of environment by:
(a) Carbon dioxide and nitrogen
(b) Carbon monoxide and carbon dioxide
(c) Ozone and carbon dioxide
(d) Nitrous oxide and sulphur dioxide
555: Consider the following statements:
1. Sweet orange plant is propagated by grafting technique.
2. Jasmine plant is propagated by layering technique.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 & 2
(d) Neither 1 nor 2
Explanation:
Jasmine is an evergreen semi vining shrub. In India, the Jasmine plant is related to Lord Shiva and Lord Vishnu. Jasmine plant is mostly propagated in summer season through the softwood cuttings, semi hard wood cuttings and through simple layering. In this technique, roots are induced on a stem before it is detached from the parent plant. In layering, the lower branch closed to the ground is bent down and covered with moist soil. After some days roots develop from the branch, which can be cut and grown independently..
Grafting: The process of joining together parts of two different plants of closely related varieties in such a manner that they live as one plant is called grafting. This is usually practiced among dicotyledonous plants, especially fruit trees. Of the two plants, one is rooted in the soil and is known as the stock. Sweet orange trees grafted on selected rootstocks fertilized with nitrogen, phosphorus and potassium.