Find **WBJEE 2014 Solved Physics Question Paper – Part 7** in this article. This paper consists of 5 questions (#31 to #35) from WBJEE 2014 Physics paper. Detailed solution of these questions has been provided so that students can match their solutions.

**Importance of Previous Years’ Paper:**

Previous years’ question papers help aspirants in understanding exam pattern, question format, important topics and assessing preparation. It has also been seen that sometimes questions are repeated in WBJEE Exam. So, this paper will certainly boost your confidence.

**31.** A metal rod is fixed rigidly at two ends so as top event its thermal expansion. If L, α and Y respectively denote the length of the rod, coefficient of linear thermal expansion and Young’s modulus of its material, then for an increase in temperature of the rod by ΔT, the longitudinal stress developed in the rod is

(A) inversely proportional to α

(B) inversely proportional to Y

(C) directly proportional to ΔT/Y

(D) independent of L

**Ans: (D)**

**Sol: **

So, stress is independent of L.

**32.** A uniform rod is suspended horizontally from its mid-point. A piece of metal whose weight is W is suspended at a distance l from the mid-point. Another weight W_{1} is suspended on the other side at a distance l_{1} from the mid-point to bring the rod to a horizontal position. When W is completely immersed in water, W_{1} needs to be kept at a distance l_{2} from the mid-point to get the rod back into horizontal position. The specific gravity of the metal piece is

**Ans: (C) **

**Sol:**

**33.** A particle is moving uniformly in a circular path of radius *r*. When it moves through an angular displacement *θ*, then the magnitude of the corresponding linear displacement will be

**Ans: (D)**

**Sol: **

**34.** A luminous object is separated from a screen by distance d. A convex lens is placed between the object and the screen such that it forms a distinct image on the screen. The maximum possible focal length of this convex lens is

(A) 4d

(B) 2d

(C) d/2

(D) d/4

**Ans: (D) **

**Sol: **

From the lens displacement method we can deduce that, the maximum possible focal length of the convex lens is d/4.

**35.** The intensity of magnetization of a bar magnet is 5 0 × 10^{4} Am^{–1}. The magnetic length and the area of cross section of the magnet are 12 cm and 1 cm^{2} respectively. The magnitude of magnetic moment of this bar magnet is (in SI unit)

(A) 0.6

(B) 1.3

(C) 1.24

(D) 2.4

**Ans: (A)**

**Sol: **

So, the magnitude of magnetic moment of this bar magnet is 0.6

**Also Get:**

**WBJEE Previous Years' Question Papers**

Previous Article WBJEE 2014 Solved Physics Question Paper – Part 8

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