Levers in Our body

Q.

Give example of each class of lever in a human body.

Q.

A radioactive substance emits radiations :

1. in the order α , β and γ one by one
2. α or β
3. X-rays and γ rays

4. α , β and γ simultaneously

Q. Name the three constituents of an atom and state mass and charge of each. How are they distributed in an atom?

Q.

Which of the following prevents undue tightening of a screw gauge?

1. Stud

2. Index

3. Ratchet

4. Screw

Q.

What type of lever is formed by the human body while (a) raising a load on the palm, and (b) raising the weight of body on toes?

Q.

Assertion: Tendon is present in all bone joints.
Reason: Tendon connects the bones at the joints & holds them in position.

1. If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.

2. If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.

3. If Assertion is correct but Reason is incorrect.

4. If both assertion and reason are false.

Q.

Why is the source of Alpha particle kept inside the lead box?

Q.

What is the name of the smallest bone in the skeletal system? Where in the body is this bone found?

Q.

Can you identify the human body parts that can be compared with levers? Name them.

Q.

Alpha particles are formed by the removal of electrons from the __________.

Q.

Which of these pairs has almost similar masses?

1. Electron- Proton

2. Neutron- Electron

3. Electron- ${}_1{}^1\mathrm{H}$

4. Neutron-${}_1{}^1\mathrm{H}$

Q. Which class of lever found in the human body is being used by a boy :
(i) When he holds a load on the palm of his hand.
(ii) When he raises the weight of his body on his toes?

Q. The figure shows a human foot. Mark the positions of load, effort and fulcrum in the foot. Name the type lever foot.

Q. Assertion :Tendons attach one bone to another bone Reason: Ligaments attach skeletal muscles to bones

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Refer to the given figures, (A, B and C) and arrange them in an order of first class lever, second class lever and third class lever.

1. B, A, C
2. C, B, A
3. A, C, B
4. C, A, B

Q.

Why are radioactive isotopes harmful?

Q. Which of the following isotopes is most dangerous to Homo sapiens?

1. Phosphorus-32
2. Strontium-90
3. Caesium-137
4. Iodine-131

Q. A gorilla like man has huge hands and legs. This is due to the abnormal secretion of

1. Pituitary FSH
2. Pituitary LH
3. Pituitary GH
4. Thyroid

Q. The $8^{th}$ and $9^{th}$ ribs are known as false ribs because their external portions are attached to

1. Xiphisternum
2. Costa of $7^{th}$ rib
3. They have no Costa
4. They are not true ribs

Q. Explain the difference between the excretory system of humans and plants.

Q.

Indicate the positions of load L, effort E and fulcrum F in the forearm shown alongside in Fig. Name the class of lever.

Q. The vertebrae which bears the whole weight of the skull is

1. Axis
2. Sacral
3. Cervical
4. Atlas

Q. The main functions/of Broca's area is/are

1. Controlling leg movements
2. Controlling tongue movements
3. Controlling hiccupp and swallowing
4. All of the above

Q. Raising the weight of the body on the toes is an example of

1. Class 3-lever
2. Class 1-lever
3. Class 2-lever
4. None of the above

Q. Mark the statement that is incorrect for smooth muscles.

1. Smooth muscles from the muscular component of the visceral organs such as blood vessels, urinary bladder, ciliary body etc
2. Smooth muscles cells do not have the troponin tropomyosin mechanism of controlling contraction
3. Irritability is shown by all smooth muscles except ciliary muscles
4. Hair root muscles and muscles on the large blood vessels are in example of multi-unit smooth muscles

Q. Fill in the blanks with appropriate words.
Haversian system is a diagnostic feature of ..........

Q. Indicate the positions of load, effort and fulcrum in the forearm shown above in fig 3.15 Name class of lever.

Q. Nodding of head is an example

1. Class I lever
2. Class III lever
3. All
4. Class II lever

Q. In the human car which bone is connected with the tympanum?

1. Incus
2. Stapes
3. Malleus
4. Auditory

Q.

When alpha particles are sent through a thin metal foil only one out of ten thousand of them rebounded. This observation led to the conclusion that

1. Positively charged particle are concentrated at the center of the atom

2. More number of electrons is revolving around the nucleus of the atom

3. Unit positive charge is only present in an atom

4. A massive sphere with more negative charge and unit positive charge is present at the center of the atom