New light to illuminate the world – the inventors of LED gets Nobel Prize 2014

According to the official press release,
The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2014 to

Isamu Akasaki

image

Meijo University, Nagoya, Japan and Nagoya University, Japan

Hiroshi Amano
Nagoya University, Japan

and

Shuji Nakamura
University of California, Santa Barbara, CA, USA

“for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources”

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Numericals from Newton’s Laws of motion based on F=ma (For calss XI students of Kendriya Vidyalaya Pattom)

Download the questions and solve them and submit on or before 9 Oct 2014

  1. A force acts for 10 s on a body of mass 10 kg after which the force ceases and the body describes 50 m in the next 5 s. Find the magnitude of the force. [Ans: 10 N]
  2. A  truck starts from rest and rolls down a hill with constant acceleration. It travels a distance od 400 m in 20s. Calculate the acceleration and the force acting on it if its mass is 7 metric tonnes. [Ans: 2 m/s2, 14000N]
  3. A motor car running aat the rate of 7 m/s can be stopped by applying brakes in 10 m. Show that total resistance to the motion, when the brakes are on is one fourth of the weight of the car.
  4. In an Xray machine, an electron is subjected top a force of 10-23 N. In how much time the electron will cover a distance of 0.1 m,? Take the mass of the electron = 10-30 kg
 

Numericals from Newton’s Laws of motion based on F=ma (For calss XI students of Kendriya Vidyalaya Pattom)

Download the questions and solve them and submit on or before 9 Oct 2014

  1. A force acts for 10 s on a body of mass 10 kg after which the force ceases and the body describes 50 m in the next 5 s. Find the magnitude of the force. [Ans: 10 N]
  2. A  truck starts from rest and rolls down a hill with constant acceleration. It travels a distance od 400 m in 20s. Calculate the acceleration and the force acting on it if its mass is 7 metric tonnes. [Ans: 2 m/s2, 14000N]
  3. A motor car running aat the rate of 7 m/s can be stopped by applying brakes in 10 m. Show that total resistance to the motion, when the brakes are on is one fourth of the weight of the car.
  4. In an Xray machine, an electron is subjected top a force of 10-23 N. In how much time the electron will cover a distance of 0.1 m,? Take the mass of the electron = 10-30 kg