PET bottles and jars are commonly used for storing edible items. PET is a very familiar form of
rayon
polyamide
polyester
acrylic
When electric current is passed through a metallic conductor, amount of heat produced in the conductor depends on its
material and thickness
material, length and thickness
material and length
length and thickness
The minerals that are required in the right amount for proper functioning of muscles are
iodine and fluorine
iron and iodine
iron and calcium
sodium and potassium
The gases present in atmosphere that cause greenhouse effect are
methane, water vapour, carbon dioxide
carbon dioxide, oxygen, nitrogen
carbon dioxide, sulphur dioxide, methane
nitrous oxide, oxygen, water vapour
When carbon dioxide is passed through clear lime water solution, it turns milky. The milky appearance of lime water is due to
presence of soluble calcium carbonate
curdling of milk due to lime in lime water
presence of impurities in lime water
presence of insoluble calcium carbonate
In order to determine acidic, basic or neutral character of solutions, a student tabulated the following results after experimentation. Which of the following observations has been tabulated correctly?
Case | Test Solution | Colour change on red litmus paper | Colour change on blue litmus paper | Acidic/Basic/neutral |
A | NaCl | No change | Red | Acidic |
B | Lime water | Blue | No change | Neutral |
C | Vinegar | No change | No change | Neutral |
D | Washing soda | Blue | No change | Basic |
C
D
A
B
B.
D
A. NaCl is a salt of strong acid and strong base, so its aqueous solution is neutral, i.e. it changes the colour of red as well as blue litmus paper.
B. Lime water is alkaline, thus changes the colour of red litmus into blue but does not affect the blue litmus paper.
C. Vinegar is acidic and turns blue litmus red but has no effect over red litmus paper.
D. Washing soda is basic and turns the red litmus paper blue but has no effect over blue litmus paper.
Which one of the following is most suited to the development of scientific skills in students?
Conducting science olympiads
Performing laboratory work
Conducting Science quiz
Organising a field visit
A Science teacher is interested to focus more on acquisition of process skills by the learners. Which of the following combination of methods of teaching should be preferred by her to achieve the objectives?
Project-cum-laboratory method
Lecture-cum-demonstration method
Assignment-cum-questioning method
Lecture-cum-discussion method
Which of the following group of words can be correctly identified with Rhizobium?
Roots of legumes, parasite, soluble nitrogen compounds
Leguminous plants, symbiotic, stem nodes
Root nodules, pitcher plant, nitrogen deficient soil
Nitrogen fixation, root nodules, leguminous plants
A laboratory thermometer shows five small divisions between the markings of 55°C and 56°C. This means that the thermometer can read correctly up to
55.2°C
55.25°C
55.1°C
55.5°C