Question:
Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ are travelling into a tunnel of length ‘L’ in parallel tracks from opposite directions with velocities
108 km/h and 72 km/h, respectively. If train ‘A’takes 35s less time than train ‘B’ to cross the
tunnel then, length ‘L’ of tunnel is :
(Given L = 60 l) 
(1) 1200 m 
(2) 2700 m 
(3) 1800 m
(4) 900 m
                                                      JEE-2024       
Solution:                
Two trains ‘A’ and ‘B’ of length ‘l’ and ‘4l’ are travelling into a tunnel of length ‘L’ in parallel tracks from opposite directions with velocities 108 km/h and 72 km/h, respectively. If train ‘A’takes 35s less time than train ‘B’ to cross the tunnel then, length ‘L’ of tunnel is : (Given L = 60 l) (1) 1200 m (2) 2700 m (3) 1800 m (4) 900 m JEE-2024

Bhautik Study is a branch of knowledge that offers comprehensive solutions to a wide range of questions, aiding in preparation for exams such as JEE, NEET, CUET and NDA. 

The magnetic field at the centre of a wire loop formed by two semi circular wires of radii R1 = 2 πm and R2 = 4π m carrying current I = 4A as per figure  given below is  a × 10^–7 T. The value of a is  ______. (Centre O is common for all segments)           

                                                                      JEE-2024