Massa l'da mozhno opredelit', ispol'zuya formulu teplovogo balansa. Kolichestvo teploty, kotoroe poglosilo lda, ravno rabote Q. Formula vyglyadit sleduyushchim obrazom:
Q = m * L,
gde m - massa lda, L - teploemkost' lda.
Teploemkost' lda L = 334 kJ/kg.
Podstaviv dannye v formulu, poluchim:
Q = m * L, 1.34 * 10^3 J = m * 334 * 10^3 J/kg,
m = 1.34 * 10^3 J / (334 * 10^3 J/kg),
m ≈ 0.004 kg.
Massa lda sostavlyaet priblizitel'no 0.004 kg.