# NEET (NTA)-National Eligibility cum Entrance Test (Medical) Physics: Questions 87 - 90 of 2320

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## Question number: 87

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MCQ▾

### Question

An express train is moving with a velocity v 1. Its driver finds another train is moving on the same track in the same direction with velocity v 2. To escape collision, driver applies a retardation a on the train, the minimum time of escaping collision will be

### Choices

Choice (4)Response

a.

t1 = t-t1

b.

t =

c.

t 1 =

d.

None of the above

## Question number: 88

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Assertion-Reason▾

### Assertion (Ꭺ)

The time period of a pendulum is given by the formula, T = 2π

### Reason (Ꭱ)

According to the principle of homogeneity of dimensions, only that formula is correct in which the dimensions of L. H. S. is equal to dimensions of R. H. S.

### Choices

Choice (4)Response

a.

Both Ꭺ and Ꭱ are false

b.

Ꭺ is false but Ꭱ is true

c.

Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ

d.

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

## Question number: 89

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MCQ▾

### Question

Wavelength of ray of light is 0.006 m. It is equal to

### Choices

Choice (4)Response

a.

60 microns

b.

6 microns

c.

6000 microns

d.

None of the above

## Question number: 90

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MCQ▾

### Question

A man throws balls with the same speed vertically upwards, one after the other at an interval of 2 seconds. What should be the speed of the throw so that more than two balls are in the sky at any time? (Given g = 9.8 m/s2)

### Choices

Choice (4)Response

a.

More than 19.6 m/s

b.

Only with speed 19.6 m/s

c.

At least 0.8 m/s

d.

Any speed less than 19.6 m/s

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