# NEET (National Eligibility cum Medical Entrance Test) Physics: Questions 68 - 70 of 2142

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## Question number: 68

MCQ▾

### Question

A physical quantity A is related to four observable a, b, c and d as follows, A =

the percentage errors of measurement in a, b, c and d are 1%, 3%, 2 % and 2 % respectively. What is the percentage error in the quantity A?

### Choices

Choice (4) Response

a.

14%

b.

7%

c.

5%

d.

12%

## Question number: 69

MCQ▾

### Question

A plane is to fly due north. The speed of the plane relative to the air is 200 km/h, and the wind is blowing from west to east at 90 km/h.

(1) The plane should head in a direction of sin-1 (0.45)

(2) The plane should head in a direction of sin-1 (0.60)

(3) The relative velocity of plane w. r. t. ground is 179 km/h

(4) The relative velocity of plane w. r. t. ground is 149 km/h

### Choices

Choice (4) Response

a.

1 and 2

b.

1, 2 and 3

c.

2 and 4

d.

1 and 3

## Question number: 70

Assertion-Reason▾

### Assertion (Ꭺ)

The magnitude of velocity of two boats relative to river is same. Both boats start simultaneously from same point on the bank may reach opposite bank simultaneously moving along different paths.

### Reason (Ꭱ)

For boats to cross the river in same time. The component of their velocity relative to river in direction normal to flow should be same.

### Choices

Choice (4) Response

a.

Ꭺ is true but Ꭱ is false

b.

Ꭺ is false but Ꭱ is true

c.

Both Ꭺ and Ꭱ are false

d.

Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ

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