# If the length of a simple pendulum is equal to the radius R of the earth, its time period will be (a) 2pie (R / g)^1/2 (b) 2pie (R / 2g)^1/2 (c) 2pie (2R / g)^1/2 (d) pie (R / 2g)^1/2

85 Points
13 years ago

Dear Ajay,

T = 2Π √ LR/g(R+L)

L is lenght , R is radius of earth

Ans: b

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Anil Pannikar

IIT Bombay

SAGAR SINGH - IIT DELHI
878 Points
13 years ago

Dear student,

If length of pendulam is equal to radius of earth then time period=2 pie root(R/g) which is option a) here

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All the best.

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Sagar Singh

B.Tech, IIT Delhi

sagarsingh24.iitd@gmail.com

askIITians Faculty 628 Points
3 years ago
Dear student,
Please find the attached solution to your problem below.

SInce, the length of pendulum is significant w.r.t Radius of Earth, we have to use the formula
T = 2Π √ LR/g(R+L)  = 2Π √ R2/g(R+R) = 2Π √R/2g
(L is length of pendulum, R is radius of earth)
Hence, b is the correct option.

Hope it helps.
Thanks and regards,
Kushagra