NDA 2017 Paper 1 | Physics Question 121 | General Science

NDA 2017 Paper 1

MCQ (Single Correct Answer)

+2.5

-0.83

A positive charge +q is placed at the centre of a hollow metallic sphere of inner radius a and outer radius b. The electric field at a distance r from the centre is denoted by E. In this regard, which one of the following statements is correct?

E = 0 for a < r < b.

E = 0 for r < a.

$$E = {q \over {4\pi {\varepsilon _0}r}}$$ for a < r < b.

$$E = {q \over {4\pi {\varepsilon _0}a}}$$ for r < a.

NDA 2018 Paper 2

MCQ (Single Correct Answer)

+2.5

-0.83

The following items consist of two statements, Statement I and Statement II. Examine these two statements carefully and select the correct answer using the codes given below.

Statement I The pitch of sound wave depends upon its frequency.

Statement II The loudness of the sound wave depends upon its amplitude.

Both the statements are true and Statement II is the correct explanation of Statement I.

Both the statements are true but Statement II is not the correct explanation of Statement I.

Statement I is true but Statement II is false.

Statement I is false but Statement II is true.

NDA 2018 Paper 2

MCQ (Single Correct Answer)

+2.5

-0.83

The following items consist of two statements, Statement I and Statement II. Examine these two statements carefully and select the correct answer using the codes given below.

Statement I Sound waves cannot propagate in vacuum.

Statement II Sound waves are elastic waves and require a medium to propagate.

Both the statements are true and Statement II is the correct explanation of Statement I.

Both the statements are true but Statement II is not the correct explanation of Statement I.

Statement I is true but Statement II is false.

Statement I is false but Statement II is true.

NDA 2018 Paper 2

MCQ (Single Correct Answer)

+2.5

-0.83

The frequency of ultrasonic waves is

less than 20 Hz

between 20 Hz and 2 kHz