SOLVED PAPER 2023 (CDS) (I) (General Studies)

Total Questions: 120

1. A sprinter feels cramps and pain in the thigh muscles after a run. This is due to accumulation of

Correct Answer: (a) lactic acid
Solution:A sprinter feels cramps and pain in the thigh muscles after a run. This is due to accumulation of lactic acid.

The lack of oxygen in muscles causes the accumulation of lactic acid, due to anaerobic respiration. The accumulation of lactic acid leads to cramps in the legs of sprinters.

2. A leaf was plucked from a plant on a sunny day and kept for 2 minutes in boiling water. It was subsequently immersed in boiling alcohol and treated with iodine solution. What will be the final colour of the leaf after the test?

Correct Answer: (c) Blue
Solution:The final colour of the leaf after the test will be blue. Since the leaf was plucked on a sunny day it is presumed that starch is present. The leaf is immersed in boiling water and alcohol to remove chlorophyll. If starch is present, the iodine will turn the colour of the leaf to blue.

3. If the red blood cells (RBCs) of human blood are isolated and are diluted in normal saline (an isotonic solution to blood), what will happen to the RBCs?

Correct Answer: (c) The RBCs will shrink.
Solution:If the red blood cells (RBCs) of human blood are isolated and are diluted in normal saline (an isotonic solution to blood), the RBCs will shrink.

4. Which one of the following statement regarding bile secreted by liver is not correct?

Correct Answer: (a) Bile contains enzymes for digestion of lipids.
Solution:Statement (a) is not correct regarding bile secreted by liver. Bile is a digestive juice secreted by the liver. Although it does not contain any digestive enzymes. It plays an important role in the digestion of fats. Bile juice has bile salts such as bilirubin and biliverdin.

5. The blood pressure of a normal human being is found to be 120/80 mmHg. These numbers represent the blood pressure at

Correct Answer: (a) ventricular contraction and ventricular relaxation, respectively.
Solution:The blood pressure of a normal human being is found to be 120/80 mmHg.

These numbers represent the blood pressure at ventricular contraction (120) and ventricular relaxation (80), respectively.

In the blood pressure 120/80, the numerator 120 indicates the pressure in arteries that have been generated due to the contraction of the ventricles. It is also called the systolic pressure. The denominator 80 represents the diastolic pressure.

6. A person burned a firecracker in fornt of a cliff and heard its echo 5 sec after it burst. The distance of the cliff from the person, if the speed of the sound is 340 m/s, is a close to

Correct Answer: (d) 850 m
Solution:Given, Sound speed (v) = 340m/s
Time (t) = 5 sec.
∵ We know that, distance
= speed time = 340 m/s x 5 sec.
= 1700 m.
i.e., 1700 meter distance travelled in 5 sec.
∵ The sound has to travel twice the
distance between the cliff and the person.
Thus, the distance of the cliff
from 1700 the person is = ¹⁷⁰⁰⁄₂  = 850m.

7. Consider the following statements about the microphone and the speaker of a mobile phone.

1. The microphone converts sound to a mechanical signal.
2. The microphone converts sound to an electrical signal.
3. The speaker converts a mechanical signal to sound.
4. The speaker converts an electrical signal to sound.

Which of the statements given above are correct?

Correct Answer: (d) 2 and 4
Solution:The following statements (2) and (4) are true about the microphone and the speaker of a mobile phone.

2. The microphone is a device that converts sound to an electrical signal and these signal goes through different channels and reaches to the receiver end. It is used in hearing aid.

4. The speaker is a device that converts an electrical signal to sound. When electrical signal reaches to the receiver then it is converted into sound. For example our earphones and headphones.

8. A 100 W electric bulb is used for 10 hours a day. How many units of electrical energy are consumed by the bulb in 3 days? (1 unit = 1 kWh)

Correct Answer: (a) 3.00
Solution:Given, power (p) = 100 w
duration = 10 hours a day
Number of days = 3 days
Now, Total energy consumed by the
bulb = power × duration × Total
days
= 100 w × 10 hrs/day × 3 day
= 3000 w hrs
= 3 kWh
= 3.00 unit,   {∵ 1 unit = 1k KWh}
Option (a) is correct.

9. The area under the velocity-time graph for a particle moving in a straight line with uniform acceleration gives

Correct Answer: (b) its net displacement.
Solution:The area under the velocity-time (v - t) graph for a particle moving in a straight line with uniform acceleration gives its net displacement

10. The power of a lens of focal length 10 cm is

Correct Answer: (c) 10 dioptre
Solution:Given, focal length (f) = 100 cm
The powerful lens is inversely
proportional to its focal length (f).
Therefore, a short focal length lens
has more power, whereas a lens of
long focus length has less power.

i.e., power (p) = (100/f cm)
P = 100/10 = 10 dioptre