class 10 ohm's law

class 10 video 

what ohm's law?

Ohm’s Law states that the current flowing through a conductor is directly proportional to the potential difference applied across its ends, provided the temperature and other physical conditions remain unchanged. Mathematically it can be represented as,

objective question based on electric current

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 https://nexttopperinstitute.blogspot.com/2020/07/class-10th-objective-questions-on.html 

Class 10       HOW TO ORGANISM REPRODUCE

Question. 1(i) What is fertilisation? Distinguish between external fertilisation and internal
fertilisation.
(ii) What is the site of fertilisation in human beings?
Answer.
(i) Fertilisation is defined as the fusion of a male gamete (sperm) with a female gamete (an ovum or egg) to form a zygote during sexual reproduction.

(ii) The site of fertilisation in human beings is in the fallopian tube of female reproductive system.

Question.2 Define the terms unisexual and bisexual giving one example of each.
Answer. Unisexual is the plant whose flowers contain either stamens or carpels but not both. Example: Papaya, Watermelon.
Bisexual is the plant whose flowers contain both stamens and carpels. Example: Hibiscus, Mustard.

Question.3 Differentiate between ‘self-pollination’ and ‘cross-pollination’. Describe double fertilisation in plants.
Answer.

During fertilisation in plants, the following events take place:
(i) One of the male gamete fuses with the female gamete present in the embryo sac.
(ii) The other male gamete fuses with the two polar nuclei in the embryo sac.
The first fusion product gives rise to the zygote while the second one forms the endosperm.
The process of two fusions occurring in the embryo sac is called double fertilisation.

Question.4 What is the effect of DNA copying which is not perfectly accurate on the reproduction process?
Answer. DNA copying is not perfectly accurate and the resultant errors are a source of variations in populations of organisms.

SHORT ANSWER TYPE QUESTIONS [2 Marks]

Question.5 What is ‘reproduction’? Mention the importance of DNA copying inreproduction.
Answer. Reproduction is the process of producing new individuals of the same species
by existing organisms of a species, i.e. parents. The importance of DNA copying in reproduction are as follows:
(i) DNA copying is called DNA replication. In this process, one copy each of replicated DNA will be passed to daughter cells.
(ii) Variations may be introduced during DNA copying. This inbuilt tendency for variation during reproduction forms the basis of evolution.

Question.6 “Variations that confer an advantage to
an individual organism only will survive in a population.” Justify.
Answer. It is because the chances of survival depend on the nature of variations and different individuals have different kinds of advantages.
For example, a bacteria that can withstand heat will survive better in a heat wave, i.e. the organisms that are fit in the competitive environment and with great variations will be able to survive and adapt. Thus, more offsprings and population with genetic variations will survive.

Question.7 Name one sexually transmitted disease
each caused due to bacterial infection and viral infection. How can these be prevented?
Answer. Sexually transmitted disease caused due to
(i) Bacterial infection is gonorrhoea, and
(ii) Viral infection is AIDS (Acquired Immune Deficiency Syndrome). These diseases can be prevented by responsible sexual behaviour such as use of condom during intercourse, etc.

Question.8(a) In the human body what is the role of
(i) seminal vesicles, and (ii) prostate gland?
(b) List two functions performed by testis in human beings.
Answer. (a) The role of seminal vesicles and the prostate gland are as follows:
(i) Seminal vesicles produce seminal plasma which is in the form of fluid makes the transport of sperms smooth.
(ii) Prostate gland secretes prostatic fluid that keeps the sperms alive and helps them to swim vigorously.
(b) Two functions performed by testis
in human beings are as follows:
(i) Formation of sperms takes place in testis.
(ii) They secrete the hormone testosterone which regulates the formation of sperms and brings changes in appearance of boys at the time of puberty.

Question.9 Illustrate the following with the help of suitable diagrams:
(i) Regeneration in Planaria.
(ii) Budding in Hydra.
Answer.

Question.10 Illustrate the following with the help of suitable diagrams:
(i) Binary Fission in Amoeba.
(ii)Leaf of Bryophyllum with buds.
Answer.

Question.11 Illustrate the following with the help of suitable diagrams:
(i) Spore formation in Rhizopus.
(ii)Multiple fission in Plasmodium.
Answer.