Shrestha India 30 Questions 42 Answers 19 Best Answers 1,154 Points View Profile 7 ShresthaGuru Asked: May 14, 20212021-05-14T06:58:59+00:00 2021-05-14T06:58:59+00:00In: Science The rating of bulb B1 is 60 V, 12 W & bulb B2 is 100 V, 100 W. Find the maximum emf of the battery so that all bulbs remain safe. 7 The rating of bulb B1 is 60 V, 12 W & bulb B2 is 100 V, 100 W. Find the maximum emf of the battery so that all bulbs remain safe. electricityphysics Share Facebook 1 Answer Voted Oldest Recent Kashyap abhishek Jhumri Telaiya , 38 Questions 20 Answers 4 Best Answers 262 Points View Profile Kashyap abhishek Competent 2021-05-21T13:37:32+00:00Added an answer on May 21, 2021 at 1:37 pm For B1, V1 = 60 V, P1 = 120 W R1 = V1²/P1 = 60²/120 = 300 Ω For B2, V2 = 100 V, P2 = 100 W R2 = V2²/P2 = 100²/100 = 100 Ω Since, B1 and B2 are connected in parallel. So, 1/Rp = 1/R1 + 1/R2 = 1/300 + 1/100 = 4/100 ⇒ Rp = 100/4 = 75 Ω So, Req across circuit = 75 + 300 + 25 = 400 Ω Current that can flow through B1 = V1/R1 = 60/300 = 1/5 A Current that can flow through B2 = V2/R2 = 100/100 = 1 A So, maximum current that can flow through the circuit so that all bulbs remain safe = 1/5 A Therefore, required e.m.f. = IReq = 1/5 x 400 = 80 V 1 Share Share Share on Facebook Share on Twitter Share on LinkedIn Share on WhatsApp Select as best answer You must login to add an answer. Username or email* Password* Remember Me! Forgot Password?